bluuebunny/crossref_metadata_2025 huggingface dataset:
A Polarized Light and Scanning Electron Microscopic Study of Human Fissure and Lingual Enamel of Unerupted Mandibular Third Molars
Authors: Ekstrand K.R. , Holmen L. , Qvortrup K.
Published: April 2003

Using histological and ultrastructural techniques the aims of this study were to investigate whether the mineralization pattern and surface microanatomy of the caries–susceptible fissure enamel were different from those on the caries–inactive lingual surface. The material consisted of 31 unerupted third mandibular molars. The specimens were initially grouped into four categories: (1) without, (2) with initial, (3) with almost completed and (4) with completed root formation. One ground section with fissure–like morphology was selected from each tooth. Using water as a medium the observed birefringence was negative along the lingual and fissure transverses in specimens with almost completed and with completed root formation, while the observed birefringence was positive at different distances in the enamel in sections representing less maturation stages. Qualitative imbibition studies revealed hypomineralized enamel in the lower part of the fissures in specimens representing almost and completed root formation. Imbibed in quinoline, parts of the hypomineralized enamel behaved like a molecular sieve due to the presence of micropores, indicating that the structural arrangement is different from that in the enamel adjacent to this areas. After division of the sections into a lingual and a buccal part, SEM features were described from lower and upper parts of the buccal fissure wall and on lingual enamel in the area corresponding to the bottom part of the fissure. The surface microanatomy varied greatly. Negative developmental irregularities such as fissures and holes were associated with the immature enamel, while matured enamel – particularly fissures – housed many positive developmental irregularities such as enamel caps and protrusions. The crystal size in the mature specimens appeared smaller and more uniform than the crystals from the immature specimens. Apart from the occurrence of hypomineralized enamel in fissures and numerous positive developmental irregularities on the fissure surface, no major differences between fissure and lingual enamel were noticed, neither with respect to mineralization pattern during final stages of tooth development nor to the degree of surface porosity prior to tooth emergence.
Dental Fluorosis and Nutritional Status of 6– to 11–Year–Old Children Living in Rural Areas of Paraíba, Brazil
Authors: Correia Sampaio F. , Ramm von der Fehr F. , Arneberg P. , Petrucci Gigante D. , Hatløy A.
Published: April 2003

The aim of this study was to investigate the relationship between nutritional status and dental fluorosis in areas with fluoride in the drinking water in Paraíba, Brazil. Rural villages of comparable low socio–economic status and stable water fluoride levels were selected. Lifelong residents (6–11 years old, n = 650) were examined for nutritional status (height–for–age index; WHO methods) and dental fluorosis of central incisors and first molars (TF index). The sample was divided into three groups according to fluoride levels in the drinking water: low (below 0.7 ppm F, n = 164), medium (between 0.7 and 1.0 ppm F, n = 360) and high (above 1.0 ppm F, n = 126). Dental fluorosis was observed in 30.5, 61.1 and 71.4% of the children in these F groups, respectively. The prevalence was significantly related to the water F concentrations (χ2 = 59.93, d.f. = 2, p<0.001). The severity of dental fluorosis ranged from TF 1 to 3 in the low F group and up to 7 in the others. Malnutrition prevalence was approximately 20% in all F groups, but was unrelated to dental fluorosis. The fairly high prevalence of dental fluorosis observed suggests that other factors may be operating.
In vitro Quantitative Microhardness Assessment of Enamel with Early Salivary Pellicles after Exposure to an Eroding Cola Drink
Authors: Maupomé G. , Aguilar-Avila M. , Medrano-Ugalde H.A. , Borges-Yáñez A.
Published: April 2003

To assess the erosive effect of a cola drink on enamel incorporating early salivary pellicles, 72 groups of human enamel slabs were immersed in fresh cola, with groups differing in that slabs were (1) incubated in whole or in clarified saliva, (2) under three regimes of frequency intake (1, 5 and 10 times/day); (3) immersed with or without agitation, and (4) the pellicle was incubated for 20 min, 6 or 24 h. Quantitative assessments were done over an 8–day interval using surface microhardness testing. Results for primary enamel showed a sharp decrease from baseline (344.2±32.4 Vickers Units; mean ±SD) to day 1 (268.9±36.8), and reached 155.2±68.6 on day 8. Results for permanent enamel were 350.8±42.2, 315.9±39.2, and 149.8±85.2. Microhardness was affected by agitation, level of intake and type of saliva, but not by the pellicle incubation interval nor the type of enamel. The joint effect of static baths and higher immersion frequency was the most important factor in decreasing hardness.
Anticaries Effect of a Component from Shiitake (an Edible Mushroom)
Authors: Shouji N. , Takada K. , Fukushima K. , Hirasawa M.
Published: April 2003

The caries–inhibiting effect of the extract from shiitake (Lentinus edodes), the most popular edible mushroom in Japan, was studied both in vitro and in vivo. Shiitake extract showed an inhibitory effect on water–insoluble glucan formation from sucrose by crude glucosyltransferases of Streptococcus mutans JC–2 and Streptococcus sobrinus OMZ–176. The firmly adherent plaque in the artificial plaque formation test was strongly inhibited by shiitake extract. The reduction of firmly adherent plaque caused an increase in the incidence of non– and loosely adherent plaque and a decrease in total plaque formation. A significantly lower caries score was observed in specific pathogen–free rats infected with S. mutans JC–2 and fed with a cariogenic diet containing 0.25% shiitake extract as compared with controls fed the cariogenic diet without shiitake extract.
Application of Magnetic Resonance Microimaging to the Study of Dental Caries
Authors: Lloyd C.H. , Scrimgeour S.N. , Chudek J.A. , Hunter G. , MacKay R.L.
Published: April 2003

Magnetic resonance microimaging (MRM) of teeth has continued to be developed. Two ways in which data can be presented have been investigated, 112–μm–thick image slices and pseudo–three–dimensional surface rendered images. Limitations of the latter have been demonstrated; the possible absence of structures having low intensity or incompleteness of the image at regions from which the signal intensity is low. This has implications for the MRM investigation of dental caries. However, all intensities are recorded and are available. Structures which give a low–intensity signal can be seen in image slices. MRM appears well suited to studying the development of dental caries, ideally in combination with other techniques. As MRM is non–destructive and non–invasive, it can be used in experiments which follow the progress of the disease, yet leaves the tissue intact for other investigations.
Effect of Four Dental Varnishes on the Colonization of Cariogenic Bacteria on Exposed Sound Root Surfaces
Authors: Ekenbäck S. Balzar , Linder L.E. , Lönnies H.
Published: April 2003

The aim of this study was to evaluate the effect of four different dental varnishes on the colonization of mutans streptococci, total streptococci and lactobacilli on exposed sound root surfaces. Sixty–five individuals were randomly allotted to one of four groups for treatment with Cervitec®  varnish containing 1% chlorhexidine and 1% thymol, a thymol varnish or one of two different fluoride varnishes, Fluor Protector and Duraphat. The varnish was applied to three buccal root surfaces in each patient at baseline and after 1 week. Dental plaque from the root surfaces was collected and analysed on four different occasions: at baseline, after 1 week, 1 month and 6 months. The Cervitec varnish caused a statistically significant reduction in the number of mutans streptococci over time. The reduction was significant at 1 week and 1 month relative to baseline. The numbers of total streptococci and lactobacilli were not significantly affected by treatment with Cervitec. No statistically significant difference over time was found for mutans streptococci, lactobacilli or total streptococci after treatment with the fluoride varnishes or the thymol varnish.
A Caries Susceptibility Classification of Tooth Surfaces by Survival Time
Authors: Hannigan A. , O’Mullane D.M. , Barry D. , Schäfer F. , Roberts A.J.
Published: April 2003

Individual tooth surfaces have vastly different susceptibilities to caries and this susceptibility also varies over time. The aim of this study was to develop a method of grouping tooth surfaces into a caries susceptibility classification based on their survival experience. The data used in the study were from a 3–year caries clinical trial. The definition of survival time was taken to be the time from the start of the trial to when a surface is recorded as decayed or filled. Cluster analysis was used to divide the tooth surfaces into groups in such a way that surfaces in the same group have similar survival time distributions. The 13 groups identified were ordered from 1 to 13 starting with the group with the shortest survival time, i.e. the occlusal surfaces of the four first molars. Approximately 80% of symmetrical pairs of tooth surfaces were in the same group. The groups obtained using cluster analysis were compared to groups defined using dental/anatomical criteria. It is concluded that the cluster analysis method developed for grouping the tooth surfaces cn provide a useful descriptive measure of caries susceptibility which can be applied to data from any longitudinal study of caries.
Optical Profilometric Study of Changes in Surface Roughness of Enamel during in vitro Demineralization
Authors: Zhang X.Z. , Anderson P. , Dowker S.E.P. , Elliott J.C.
Published: April 2003

The application of non–contact optical profilometry for non–destructive study of changes in the surface roughness of natural enamel surfaces during in vitro demineralization was investigated. Repeated measurement of profiles of the same enamel surfaces after successive demineralization episodes was achieved by a kinematic specimen mount that could be removed, then accurately repositioned. Surface roughness parameters and reflectivity of natural enamel surfaces exposed to either a demineralizing solution (test) or deionized water (control) for up to 6 days were measured at 6– to 24–hour intervals. The results prior to demineralization showed that surface roughness varies with position on the enamel surface. During demineralization there was an approximately linear increase in surface roughness for the first 70 h followed by somewhat erratic behaviour, and a saturating exponential with time increase in reflectivity for the first 70 h which subsequently remained constant. Changes in enamel surface during in vitro demineralization were also observed using scanning electron microscopy.
Detection of Natural White Spot Caries Lesions by an Ultrasonic System
Authors: Çalışkan Yanıkoğlu F. , Öztürk F. , Hayran O. , Analoui M. , Stookey G.K.
Published: April 2003

Ultrasound has been used in industrial business as one of the nondestructive measurement methods. It was hypothesized that nondestructiveness of the ultrasonics could be useful in determination of demineralization of noncavitated carious lesions on human enamel. This investigation was designed to determine the presence of natural carious lesions on proximal surfaces of human molar teeth using an ultrasonic system compared to radiography and histology as the gold standards. Measurements were made directly from proximal surfaces of 20 mandible molar teeth with white spot carious lesion by 2 examiners independently with the ultrasonic system. Ultrasonic evaluation of each natural white spot lesion had a sensitivity of 88%, specificity of 86%, positive predictive value of 88% and a negative predictive value of 86%, and the chance–corrected agreement was also satisfactory (κ=0.74) compared to histology. The radiograph demonstrated chance–corrected agreement of 0.41:0.38 for the first and second examiners, respectively. Duncan test analysis of the numerical values was significantly different for the intact and the noncavitated carious surfaces (p<0.05). The results indicated that the ultrasonic evaluation is a sensitive method for the detection of the natural white spot carious lesions and can differentiate the changes in elastic properties of enamel numerically.
Effects of Apis mellifera Propolis on the Activities of Streptococcal Glucosyltransferases in Solution and Adsorbed onto Saliva–Coated Hydroxyapatite
Authors: Koo Hyun , Vacca Smith Anne M. , Bowen William H. , Rosalen Pedro L. , Cury Jaime A. , Park Yong K.
Published: April 2003

Propolis, a resinous hive product collected by Apis mellifera bees, has been used for thousands of years in folk medicine. Ethanolic extracts of propolis (EEP) have been shown to inhibit the activity of a mixture of crude glucosyltransferase (Gtf) enzymes in solution. These enzymes synthesize glucans from sucrose, which are important for the formation of pathogenic dental plaque. In the present study, the effects of propolis from two different regions of Brazil on the activity of separate, purified Gtf enzymes in solution and on the surface of saliva–coated hydroxyapatite (sHA) beads were evaluated. The EEP from Minas Gerais (MG; Southeastern Brazil) and Rio Grande do Sul (RS; Southern Brazil) were tested for their ability to inhibit the enzymes GtfB (synthesis of insoluble glucan), GtfC (insoluble/soluble glucan) and GtfD (soluble glucan). The effects of propolis on Gtf from Streptococcus sanguis (soluble glucan synthesis) was also explored. The EEP from both regions effectively inhibited the activity of all Gtfs in solution (75–95%) and on the surface of sHA beads (45–95%) at concentrations between 0.75 and 3.0 mg of propolis/ml. However, the two samples of propolis showed different levels of inhibition on each of the enzymes tested. In general, EEP RS demonstrated a significantly higher inhibitory activity on GtfB and C activities (both solution and surface assays) than EEP MG at concentrations between 0.047 and 0.187 mg/ml (p<0.05). EEP MG, on the other hand, exhibited a greater inhibitory effect on the activities of surface GtfD (at 0.375, 0.75 and 1.5 mg/ml) and S. sanguis Gtf (at 1.5 and 3.0 mg/ml; p<0.05). These data indicate that EEP is a potent inhibitor of Gtf enzymes in solution and adsorbed on an experimental pellicle; however, its effect on Gtf activity is variable depending on the geographical origin of the propolis samples. There is a need to identify the active compounds of propolis.
Epithelial-Mesenchymal Interactions in Development of the Mouse Fetal Genital Tubercle
Authors: Kurzrock Eric A. , Baskin Laurence S. , Li Yingwu , Cunha Gerald R.
Published: April 2003

Epithelial-mesenchymal interactions play a central role in the development of urogenital organs. We hypothesized that normal development of the external genitalia depends upon proper mesenchymal-epithelial signaling. The mesenchyme of the adult mouse penis consists of a corpus cavernosum and proximal and distal bones. The differentiation of penile mesenchyme into bone and cartilage begins after birth and can be accelerated by androgens. After determining the sex, genital tubercles of fetal mice at gestational day 15 were removed. The genital tubercles were trypsinized and microdissected to remove the epidermis and urethra from the mesenchyme. Recombinant specimens were created by combining genital tubercle mesenchyme with genital tubercle epithelium, bladder epithelium or tail epidermis. Tissues were grafted under the renal capsule of male athymic mice. After 3 weeks of growth, grafts were removed from the kidney, weighed and stained with hematoxylin and eosin, Alcian blue and peanut agglutinin. Male and female grafts showed no difference in growth or differentiation. Intact grafts and recombinant grafts, irrespective of the epithelial source, grew significantly more than grafts of the mesenchyme only. Recombinant grafts demonstrated a significantly higher prevalence of cartilage formation and mesenchymal differentiation compared to grafts of the mesenchyme without epithelium. Since heterologous epithelium is able to induce equivalent growth and differentiation of phallic mesenchyme, epithelium carries a permissive, but critical, role in genital mesenchyme development.
Oct-4: Lessons of Totipotency from Embryonic Stem Cells
Authors: Pesce Maurizio , Anastassiadis Konstantinos , Schöler Hans R.
Published: April 2003

The Oct-4 transcription factor is expressed in embryonic stem cells and germ cells of the mouse embryo. Cells that are driven into embryonic and extraembryonic somatic differentiation lose Oct-4 expression. Oct-4 is crucial for the maintenance of the totipotency of embryonic cells at early developmental stages as demonstrated recently by homologous recombination. Since during embryogenesis Oct-4 is restricted to germ cells, it is possible that it plays a key role for the germline lineage by preventing differentiation of these cells during gastrulation. Thus, Oct-4 appears to be a key regulator of totipotency during the life cycle of mammals.
Immunocontraception with Zona pellucida Proteins
Authors: Paterson Margaret , Jennings Zoë A. , van Duin Marcel , Aitken R. John
Published: April 2003

The prospect of an immunological approach to contraception that would disrupt the process of fertilisation itself has resulted in a considerable interest into research in this area. It has been known for some time that antibodies raised against the zona pellucida (ZP) can suppress fertility very effectively. However, the initial optimism of this approach has been marred by the appearance of an ovarian pathology characterised by disruption of folliculogenesis and depletion of the primordial follicle pool. Adverse auto-immune reactions have been observed in the ovaries of mice after the induction of immunity with mouse ZP3 epitopes. However, this was associated with lymphocytic infiltration of the ovarian stroma, which could be circumvented by careful selection of B-cell epitopes to induce reversible infertility. In order to identify similar epitopes on primate ZP3, epitope-mapping studies were performed and incorporated into chimeric vaccines that included a promiscuous T-helper cell epitope. Both single and triple peptide vaccines have been evaluated in vivo and no detrimental effects on ovarian function were observed. The resulting high titre antibodies bound exclusively to the ZP of marmoset and human ovarian sections and could suppress in vitro human sperm-egg binding by approximately 60%, but did not prevent pregnancy in actively immunised female marmosets. Thus, considerable research is still required to identify a combination of ZP3 epitopes that will induce infertility free of any unwanted side effects.
Systemic Mastocytosis
Authors: Karnam Umaprasanna , Rogers Arvey
Published: April 2003

Mastocytosis is a disease characterized by an abnormal increase in mast cells. Rare in occurrence, protean in its manifestations, it is a disease which is very seldom thought of and hence, possibly even overlooked. The last few decades have witnessed an upsurge in the understanding of the physiology and pathobiology of mast cells. Better means for diagnosis and follow-up have become available. Once a diagnosis is established histamine antagonists remain the mainstay of treatment. Most patients live and die with the disease rather than of it. The objective of this review is to discuss this entity with a special focus on diagnosis and treatment.
Are Constipated Children Different from Constipated Adults?
Authors: Solzi Gabriel , Di Lorenzo Carlo
Published: April 2003

Constipation represents a diagnostic category of high prevalence both in children and adults, but with low disability and hospitalization rates. This review is written to be a relatively practical guide to physicians providing information for the evaluation and management of one of the most common chronic digestive disorders. In this article we emphasize the differences between constipation in children and adults. The approach to childhood constipation needs to focus on the behavioral nature of this disorder. Diagnostic techniques often used in constipated adults may not provide useful data when applied to children. Treatment of childhood constipation requires a team effort involving the physician, parents and child.
A Report of a Gastrinoma Localized Preoperatively by Endoscopic Ultrasound Only and a Review of the Approach to Imaging in Zollinger-Ellison Syndrome
Authors: Bloomfeld Richard , Bornstein Jeffrey , Jowell Paul
Published: April 2003

The addition of somatostatin receptor scintigraphy and endoscopic ultrasound to the preoperative assessment of patients with Zollinger-Ellison syndrome has improved the ability to localize gastrinomas. We report a patient with Zollinger-Ellison syndrome with a gastrinoma localized preoperatively by endoscopic ultrasound only. We review the literature regarding the sensitivity of somatostatin receptor scintigraphy and endoscopic ultrasound and discuss the approach to imaging in Zollinger-Ellison syndrome.
Esophageal Cast: A Manifestation of Graft-versus-Host Disease
Authors: Nakshabendi Imad , Maldonado Martin , Coppola Domenico , Mamel Jay
Published: April 2003

Diffuse involvement of the gastrointestinal tract by graft-versus-host disease (GVHD) is a common complication of bone marrow transplantation. The esophageal involvement in this disease tends to be a vesiculobullous, ulcerative or desquamative process. To our knowledge, esophageal cast has not been described in the context of GVHD. However, it has been described as a result of trauma to the esophagus or in association with bullous disease of the skin. We present a case of esophageal cast in a patient with chronic GVHD following bone marrow transplant.
The Caregiving Burden Scale among Chinese Caregivers of Alzheimer Patients
Authors: Fuh Jong-Ling , Wang Shuu-Jiun , Liu Hsiu-Chih , Wang Hasio-Chien
Published: April 2003

From April 1996 to January 1997, a total of 76 Alzheimer’s disease (AD) patients and their caregivers were recruited for participation in a comprehensive assessment at the Veterans General Hospital-Taipei, a 2,198-bed tertiary-care teaching hospital in Taipei, Taiwan. The AD patients responded to the Chinese version of the Cognitive Abilities Screening Instrument. Primary caregivers rated the patients using the Symptom Check List-90 (SLC-90) and the Revised Memory and Behavior Problems Checklist and then rated themselves with the caregiving burden scale (CBS), coping strategies scale and the short version of the Geriatric Depression Score (GDS-S). The internal consistency of the CBS, as assessed by Cronbach’s α, was 0.849. The correlations between the CBS, SCL-90 and GDS-S ranged from 0.435 to 0.698. The CBS scores increased with disease progression and were higher among spouse caregivers than adult children caregivers. Multiple-regression analysis revealed that caregivers with higher CBS scores were more likely to have lower education levels and to use the meaning subscales of coping strategies, and that these caregivers’ patients had greater disruptive behavior and were older (R2 = 0.727, p = 0.001). The current study establishes the reliability and validity of the Chinese version of the CBS for assessment of Chinese caregivers of AD patients.
Dopaminergic Control of Kynurenate Levels and N-Methyl-D-Aspartate Toxicity in the Developing Rat Striatum
Authors: Poeggeler Burkhard , Rassoulpour Arash , Guidetti Paolo , Wu Hui-Qiu , Schwarcz Robert
Published: April 2003

This study was designed to examine the effects of d-amphetamine (D-AMPH) and D1- and D2-selective dopaminergic drugs on the concentration of the broad-spectrum excitatory amino acid receptor antagonist kynurenic acid (KYNA) in the striatum of developing and adult rats. At all ages, KYNA levels were significantly reduced 1 h after the systemic administration of D-AMPH (5 mg/kg). SKF 38393 (5 mg/kg) and quinpirole (2 mg/kg) also caused a rapid decrease in striatal KYNA, but only in postnatal day (PND) 7 and 14 rats. All these effects were readily prevented by specific dopamine receptor antagonists. The possible functional significance of the reduction in KYNA levels was tested in PND 14 animals. When pretreated with D-AMPH (5 mg/kg), these rats showed markedly increased vulnerability to an intrastriatal injection of the excitotoxin NMDA. These data suggest that KYNA plays a role as a mediator of dopamine-glutamate interactions in the rat striatum.
Postnatal Development of Glutamate Receptor-Mediated Responses in the Neostriatum
Authors: Colwell Christopher S. , Cepeda Carlos , Crawford Cynthia , Levine Michael S.
Published: April 2003

Three experimental approaches were used to examine the maturation of N-methyl-D-aspartate (NMDA) receptors in the neostriatum and compare their developmental profile to that of the non-NMDA receptors [α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) and kainate (KA)]. The first, and least conventional approach utilized infrared videomicroscopy to measure NMDA-induced swelling in single cells in a brain slice. The results demonstrated that NMDA receptors display an incremental pattern of postnatal development with no responses at postnatal day (PND) 3, weak responses at PND 7, the largest responses by PND 14 and slight decreases at PNDs 21 and 28. At PNDs 3 and 7, KA-induced cell swelling was proportionately greater than NMDA-induced cell swelling suggesting earlier maturation of this non-NMDA receptor subtype. The second approach used whole-cell patch clamp analysis to examine NMDA currents and compare their maturation to AMPA/KA-induced currents. Though the data are still preliminary, a very similar developmental pattern emerged. NMDA-induced currents were small and developed slowly after PND 7. In contrast, AMPA/KA-induced currents were larger and appeared to develop earlier. Finally, dizocilpine (MK-801) binding was measured in homogenates of neostriatal tissue. The ontogeny of binding resembled a step function with increases between PNDs 3 and 7 and PNDs 14 and 21. Binding peaked at PND 28 and then declined slightly in the adult (PND 60). The affinity of MK-801 for the receptor did not change during postnatal development. These findings demonstrate the pattern of functional development of glutamate receptors in the neostriatum. The NMDA receptor subtype displays minimal functional development until PND 14. In contrast, neostriatal AMPA/KA receptor function appears to precede NMDA receptor function.
Localized in vivo 13C-NMR of Glutamate Metabolism in the Human Brain: Initial Results at 4 Tesla
Authors: Gruetter Rolf , Seaquist Elizabeth R. , Kim Suckwon , Ugurbil Kâmil
Published: April 2003

Using optimized administration of 13C-labeled glucose, the time course of the specific activity of glucose was measured directly by in vivo 13C-NMR in the human brain at 4 Tesla. Subsequent label incorporation was measured at the C2, C3 and C4 positions of both glutamate and the well-resolved C2, C3 and C4 resonances of glutamine and at the C2 and C3 positions of aspartate. GABA was clearly observed for the first time in vivo, suggesting a substantial GABA turnover in the normal human visual cortex. Likewise, lactate C3 labeled with an estimated active pool size on the order of 0.5 mM. A model of cerebral glutamate metabolism is proposed which predicts that glutamatergic action (‘neurotransmission’), pyruvate carboxylase flux, TCA cycle activity, glucose consumption and exchange across the mitochondrial membrane can be assessed simultaneously in the human brain.
Metabolic Control of Kynurenic Acid Formation in the Rat Brain
Authors: Hodgkins Paul S. , Schwarcz Robert
Published: April 2003

Excitotoxic neuronal loss can be precipitated by defects in cerebral energy metabolism. Antagonists of excitatory amino acid receptors, such as the endogenous metabolite kynurenic acid, can effectively block excitotoxic lesions. Using brain tissue slices, the present study was designed to examine a potential link between metabolic status and cerebral kynurenic acid formation in adult rats. The results demonstrate that fluctuations in cerebral energy metabolism are closely associated with changes in kynurenic acid synthesis. Taken together, the data are compatible with the idea that the production of kynurenic acid in the brain is critically affected by the availability of pyruvate or other 2-oxoacids (i.e. co-substrates for the enzymatic transamination of the bioprecursor of kynurenic acid, L-kynurenine). Such metabolic control of kynurenic acid function may play a role in excitotoxic brain diseases
Tenascin-Y in the Developing and Adult Avian Nervous System
Authors: Tucker Richard P. , Hagios Carmen , Chiquet-Ehrismann Ruth
Published: April 2003

The glycoproteins tenascin-C and tenascin-R are abundant in the developing and adult nervous system, respectively. We have used a polyclonal antiserum to determine if tenascin-Y, a novel member of the tenascin family previously identified in the extracellular matrix of muscle, is also expressed in the avian nervous system. Beginning at embryonic day 3 tenascin-Y immunoreactivity is associated with bottle-shaped ependymal cells in the roof plate and floor plate of the spinal cord and brain. These cells resemble the secretory cells that synthesize the ventricular extracellular matrix, including Reissner’s fiber. Tenascin-Y immunoreactivity is also seen in pia mater and blood vessels in the developing and adult central nervous system. Anti-tenascin-Y stains the connective tissue sheath of peripheral nerves and the dorsal roots beginning around embryonic day 20. In vitro, sensory neurites fail to form lamellipodia when cultured in the presence of recombinant tenascin-Y, suggesting that tenascin-Y may play a role in inhibiting sensory neurite regeneration into the spinal cord. There is little overlap in the expression patterns of tenascin-Y and tenascin-C during development and between tenascin-Y and tenascin-R in the adult central nervous system, which is further evidence of distinctive mechanisms of gene regulation by the different members of the tenascin family.
Dual Role of GABA in the Neonatal Rat Hippocampus
Authors: Khalilov Ilgam , Dzhala Volodymyr , Ben-Ari Yehezkel , Khazipov Roustem
Published: April 2003

The effects of modulators of GABA-A receptors on neuronal network activity were studied in the neonatal (postnatal days 0–5) rat hippocampus in vitro. Under control conditions, the physiological pattern of activity of the neonatal hippocampal network was characterized by spontaneous network-driven giant depolarizing potentials (GDPs). The GABA-A receptor agonist isoguvacine (1–2 μM) and the allosteric modulator diazepam (2 μM) induced biphasic responses: initially the frequency of GDPs increased 3 to 4 fold followed by blockade of GDPs and desynchronization of the network activity. The GABA-A receptor antagonists bicuculline (10 μM) and picrotoxin (100 μM) blocked GDPs and induced glutamate (AMPA and NMDA)-receptor-mediated interictal- and ictal-like activities in the hippocampal slices and the intact hippocampus. These data suggest that at early postnatal ages GABA can exert a dual – both excitatory and inhibitory – action on the network activity.
Path Analysis Shows That Increasing Ketogenic Ratio, but Not β-Hydroxybutyrate, Elevates Seizure Threshold in the Rat
Authors: Bough Kristopher J. , Chen Ru San , Eagles Douglas A.
Published: April 2003

Previous work has identified several criteria that may be important in determining the efficacy of the ketogenic diet as a treatment for intractable epilepsy in children. The present study was designed to investigate the influence of four major variables on seizure threshold, i.e. ketogenic ratio, body weight, age at diet onset and β-hydroxybutyrate in rats. Path analysis was used to statistically model and quantify the causal relationships among variables. Results indicate that seizure threshold was significantly elevated with increasing ketogenic ratios (i.e. more fats vs. carbohydrates and proteins) and decreasing weight. Conversely, age at diet onset and plasma levels of β-OHB showed no causal relation to seizure resistance. These results suggest that the efficacy of the ketogenic diet is independent of the level of ketonemia but is markedly influenced by diet and growth.
Hippocampal Chemical Anatomy in Pediatric and Adolescent Patients with Hippocampal or Extrahippocampal Epilepsy
Authors: Ying Z. , Babb T.L. , Hilbig A. , Wyllie E. , Mohamed A. , Bingaman W. , Prayson R. , Staugaitis S. , Najm I. , Lüders H.O.
Published: April 2003

We determined whether age or seizure types were associated with hippocampal neuron loss, mossy fiber (MF) and GABAergic synaptic reorganizations or postsynaptic receptor densities. Children and adolescents were grouped into: (1) nonhippocampal sclerosis (non-HS; n = 11) and (2) hippocampal sclerosis (HS; n = 11). The most important results showed that: (1) regardless of the etiology of the seizures, there were greater cell losses in Ammon’s horn with older ages in years; in the non-HS group, cell losses were greater with the older ages or with longer epilepsy durations; however, in the HS patients, the cell losses were not related to the patients’ ages or epilepsy durations; (2) in both HS and non-HS, CA1 had greater cell losses than CA4; (3) in HS, CA1 and CA4 had greater cell losses than those in non-HS; (4) in non-HS, MF sprouting was greater with ages or with longer epilepsy durations; by contrast, in HS, MF sprouting was not related to the patients’ age or epilepsy duration; (5) densities for AMPA GluR1, GABA-Aβ and for GABA axonal terminals were positively increased with age. These findings support the hypothesis that hippocampal cell losses and aberrant synaptic reorganizations are greater in the hippocampi of adolescents than in children, even for non-HS pathologies.
Exploiting the Dynamics of S-Phase Tracers in Developing Brain: Interkinetic Nuclear Migration for Cells Entering versus Leavingthe S-Phase
Authors: Hayes Nancy L. , Nowakowski Richard S.
Published: April 2003

Two S-phase markers for in vivo studies of cell proliferation in the developing central nervous system, tritiated thymidine (3H-TdR) and bromodeoxyuridine (BUdR), were compared using double-labeling techniques in the developing mouse cortex at embryonic day 14 (E14). The labeling efficiencies and detectability of the two tracers were approximately equivalent, and there was no evidence of significant tracer interactions that depend on order of administration. For both tracers, the loading time needed to label an S-phase cell to detectability is estimated at <0.2 h shortly after the injection of the label, but, as the concentration of the label falls, it increases to ∼0.65 h after about 30 min. Thereafter, cells that enter the S-phase continue to become detectably labeled for ∼5–6 h. The approximate equivalence of these two tracers was exploited to observe directly the numbers and positions of nuclei entering (labeled with the second tracer only) and leaving (labeled with the first tracer only) the S-phase. As expected, the numbers of nuclei entering and leaving the S-phase both increased as the interval between the two injections lengthened. Also, nuclei leaving the S-phase rapidly move towards the ventricular surface during G2, but, unexpectedly, the distribution of the entering nuclei does not differ significantly from the distribution of the nuclei in the S-phase. This indicates that: (1) the extent and rate of abventricular nuclear movement during G1 is variable, such that not all nuclei traverse the entire width of the ventricular zone, and (2) interkinetic nuclear movements are minimal during S-phase.
Precursor Cells in the Subventricular Zone of the Adult Mouse Are Actively Inhibited from Differentiating into Neurons
Authors: Dutton Renée , Bartlett Perry F.
Published: April 2003

The adult mouse subventricular zone (SVZ) contains precursor cells capable of generating new neurons which populate the olfactory bulb. The SVZ precursors, however, appear to be restricted in their capacity to generate neurons in other regions of the brain indicating a tight regulation of their differentiation. We demonstrate in vitro that explants of SVZ are unable to generate neurons from dividing precursors, even though precursors are present and dividing within explant cultures. However, when plated as single cells in fibroblast growth factor-1 or with no growth factor, approximately 1% of harvested cells gave rise to clones containing neurons and astrocytes, indicating that bipotential precursors were present in the explants. Inhibitory effects of cell density were more directly shown by plating freshly isolated SVZ cells, or explant-derived SVZ cells, at increasing cell density. The frequency of neuron-containing wells was found to be greatly reduced at higher cell concentrations: >100 cells/well in the case of explant-derived cells and >500 cells in the case of freshly isolated cells. Thus, it appears that the precursor’s ability to generate neurons is actively inhibited by paracrine mechanisms which may be mediated by either cell-cell contact or by short-range factors.
Cellular and Subcellular Localization of Necdin in Fetal and Adult Mouse Brain
Authors: Niinobe Michio , Koyama Kazuya , Yoshikawa Kazuaki
Published: April 2003

Necdin is a 325-amino-acid residue protein encoded by a cDNA clone isolated from neurally differentiated embryonal carcinoma cells. Ectopic expression of necdin induces growth arrest of proliferative cells. Necdin binds to major transcription factors E2F1 and p53, suggesting that necdin exerts its functions through the interactions with these cell-cycle-regulating factors. However, information about precise localization of endogenous necdin protein is currently lacking. A rabbit polyclonal antibody was raised against a bacterially expressed recombinant protein of necdin (amino acids 83–325). Immunoblot analysis revealed that necdin protein was expressed almost exclusively in the brain of adult mice. A relative molecular mass of endogenous necdin was estimated at approximately 43,000. In developing mouse brain, necdin was most abundant during fetal and neonatal periods. Necdin was highly enriched in the cytoplasm of hypothalamic neurons in fetal and adult mice. The subcellular fractionation analysis revealed that necdin was concentrated in the cytosol fraction of brain cells. These results suggest that endogenous necdin protein is localized predominantly in the cytoplasm of differentiated neurons and moves into the nucleus under specific conditions.
The Role of Dietary n–6 and n–3 Fatty Acids in the Developing Brain
Authors: Innis Sheila M.
Published: April 2003

The dietary requirements for essential fatty acids and the possibility of a specific role for the polyunsaturated fatty acid docosahexaenoic acid (DHA) is one of the most controversial areas in infant nutrition. DHA is found in unusually high concentrations in the brain and is selectively accumulated during fetal and infant brain growth. DHA can be synthesised through a complex series of chain elongation-desaturation reactions from α-linolenic acid, but the efficiency of this process in young infants is not clear. Clinical studies on the potential benefits to neural development of dietary DHA have yielded conflicting results. Recent studies have provided evidence that plasma DHA is available to developing brain and that DHA is involved in dopamine and serotonin metabolism. These findings should guide clinical studies to more sensitive measures of the functional roles of dietary n–3 fatty acids and to clinical conditions where n–3 fatty acids may have benefit.
A Review of Infantile and PediatricAcne
Authors: W. Lucky Anne
Published: April 2003

Acne occurs primarily in the first year of life and at puberty. Neonatal and infantile acne may reflect the relatively high androgens from the adrenal in girls and the adrenal and testes in boys characteristic of this age. Early in puberty, acne in boys and girls is primarily comedonal and midfacial. The best predictors of severe acne are early onset of comedones and serum levels of dehydroepiandrosterone sulfate. Early recognition and therapy of acne may prevent scarring and psychological stress.
Ulcerative Porokeratosis
Authors: Watanabe T. , Murakami T. , Okochi H. , Kikuchi K. , Furue M.
Published: April 2003

A 54-year-old man presented with multiple annular plaques since infancy. During the intake of nifedipine and nitroglycerin over a period of 6 years, reddish, eruptive and ulcerative changes were seen in the pre-existing skin lesions on the penis, scrotum and legs. In addition to a typical cornoid lamella, histological examination revealed a band-like infiltration beneath the epidermis, liquefaction degeneration of the basal cell layer and subsequent coagulative necrosis of the keratinocytes. We review similar ulcerative types of porokeratosis in the literature and discuss the significance of our unusual case.
Superficial Granulomatous Pyoderma
Authors: del Cerro Heredero M. , Sánchez Yus E. , Gómez-Calcerrada M.R. , Herrera Sánchez M. , Suárez Fernández R. , de Eusebio Murillo E.
Published: April 2003

Superficial granulomatous pyoderma (SGP) is a form of pyoderma gangrenosum (PG) characterized by superficial ulceration and chronic course. To date it has been described as a condition with specific histopathological findings. We report a new case with clinical characteristics of SGP and describe why we believe that the histological changes previously described are not typical of this entity.
Detection of Human Papillomavirus Type 33 DNA in Extragenital Bowen’s Disease with the Polymerase Chain Reaction
Authors: Deguchi M. , Tomioka Y. , Mizugaki M. , Tagami H.
Published: April 2003

Background: Data on the association of human papillomavirus (HPV) infection with extragenital Bowen’s disease are very scarce. Objective: To evaluate the prevalence of HPV infection in extragenital Bowen’s disease showing histologically a number of koilocytes in the lesional epidermis, we studied formalin-fixed, paraffin-embedded tissues of 9 such cases. Methods: HPV DNA was studied in such samples by the polymerase chain reaction (PCR) and in situ hybridization. Results: Despite negative results with in situ hybridization, the PCR with HPV type 33 primer detected the presence of virus DNA in 2 out of 9 cases. Conclusion: As far as we know, this is the first report of the detection of HPV type 33 DNA in the lesional skin of extragenital Bowen’s disease. The prevalence of HPV infection in extragenital Bowen’s disease may be higher than expected, especially in cases histologically showing many koilocytes in the lesional epidermis.
Cutaneous Mastocytosis in Adults
Authors: Tebbe B. , Stavropoulos P.G. , Krasagakis K. , Orfanos C.E.
Published: April 2003

Background and Objective: Systemic mastocytosis is a rather rare disorder involving the skin and several other organs. The aim of this study was to analyse the extent of extracutaneous manifestations in 14 adult patients who presented with prominent cutaneous involvement within the last 5 years. Results: The cutaneous lesions were clinically diagnosed as telangiectasia macularis eruptiva perstans in 2 patients, urticaria pigmentosa of varying extent in 11 and diffuse erythrodermic mastocytosis in 1 patient. All patients had extracutaneous manifestations with involvement of one additional organ system in 6/14 cases, two in 5/14 and three in 3/14. Ten out of 14 patients suffered from generalized pruritus, and 11/14 reported mild wheal formation, while 3/14 with multi-organ involvement mentioned recurrent flushing episodes. The gastro-intestinal tract was involved in 8/14 cases with an increase in gastric and colon mucosal mast cells in 5/8 cases and gastroduodenitis in 2. Bone marrow involvement was seen in 7/13 patients, hepatosplenomegaly in 2, anaemia in 2 and thrombocytopenia in 3. The disease had a duration of 0.5–32 years, clinical symptoms remaining basically unchanged. Malignant transformation was not seen; only 1 patient developed myelodysplastic syndrome within 2 years after the first cutaneous lesions. Conclusions: Our study shows that extracutaneous involvement should be carefully considered in adult patients with cutaneous mastocytosis. Systemic multi-organ mast cell disease in adults is a long-lasting disorder with recurrent episodes of varying clinical symptomatology. However, the disease shows rather slow progression, and malignant transformation is rare. Satisfactory management is achieved by symptomatic oral drug intake.
Cigarette Smoking as a Triggering Factor of Hidradenitis suppurativa
Authors: König A. , Lehmann C. , Rompel R. , Happle R.
Published: April 2003

Background: Hidradenitis suppurativa is a chronic inflammatory skin disease involving the axillary, inguinal and anogenital regions and sometimes, in addition, the submammary or sacral areas. The etiology of this condition is unknown. Objective: A matched-pair case-control study was performed to evaluate the influence of smoking habits on the manifestation of this disease. Methods: Patients who had received surgical treatment for hidradenitis suppurativa in two dermatological centers completed a questionnaire dealing with family history, course of the disease and smoking habits. To form a randomized matched-pair control group, an equal number of patients admitted for various other skin diseases such as atopic dermatitis, varicose veins, skin tattoos, alopecia areata or melanoma was matched for sex and age and evaluated for smoking habits. Statistical analysis was performed by use of several χ2 tests in a cross-table setting. Moreover, a comparison to the expected smoking prevalence in Germany based on national statistics was performed. Results: Out of 84 patients treated for hidradenitis suppurativa, 63 subjects (27 men, 36 women) completed the questionnaire. The rate of active cigarette smokers was 88.9% (56 patients), whereas 4 subjects (6.4%) had never smoked. 3 patients (4.8%) stated to be ex-smokers, but 2 of these had quit smoking only recently and after onset of the disease. The rate of smokers in the matched-pair control group was 46%. The significantly higher proportion of active smokers among patients with hidradenitis suppurativa can be expressed by an odds ratio of 9.4, the calculated 95% confidence interval was 3.7–23.7 (p < 0.001). The expected smoking prevalence in Germany was 26.7% according to national statistics. 73% of our patients had no family history of hidradenitis suppurativa whereas 27% reported at least one affected first-degree relative. Conclusion: From the exceedingly high rate of smokers among patients with this condition we conclude that cigarette smoking is a major triggering factor of hidradenitis suppurativa. Remarkably, the disease can be categorized as a smoking sequel that is neither of vascular nor neoplastic nature. Because familial occurrence was rather rarely reported, and because an environmental factor in the form of cigarette smoking appears to be of crucial importance to trigger the disease, we assume that the genetic basis of hidradenitis suppurativa is polygenic rather than mendelian. Smoking cessation should be encouraged particularly in patients with hidradenitis suppurativa although it is unknown whether this improves the course of the disease.