bluuebunny/crossref_metadata_2025 huggingface dataset:
Malnutrition and Developmental Defects of Enamel in 2- to 6 -Year-Old Saudi Boys
Authors: Rugg-Gunn A.  J. , Al-Mohammadi S.  M. , Butler T.  J.
Published: April 2003

Three hundred and ninety boys aged 2, 4 or 6 years from Riyadh, Saudi Arabia, took part in a survey in 1993/94. The main aims of the study were first, to identify factors related to malnutrition in young children since a study of older children from the same area 1 year before had shown malnutrition to be strongly related to prevalence of developmental defects of enamel (DDE) of permanent teeth and, second, to identify factors related to the prevalence of developmental defects of primary teeth. Enamel defects were recorded by clinical examination of the buccal surfaces of all primary teeth by 1 examiner using the DDE index. A questionnaire to parents provided information on socio-economic status, illness in the mother and child, infant feeding, trauma to teeth and toothbrushing. A 24-hour dietary record, to estimate water and milk intake, and a 24-hour urine collection were obtained for each child twice. Nutritional status was calculated from height for age using WHO methods. Multiple regression analyses revealed four variables related (p < 0.05) to malnourished status: low birth-weight, low volume of water drunk, child stopped breast- and bottle-feeding before 1 year of age, and low class urban or rural area of residence. Birth-weight was itself related to area of residence (p = 0.02), parental education (p = 0.02) and maternal illness during pregnancy (p = 0.06). Malnutrition (p < 0.001), low birth-weight (p < 0.001), childhood illness (p < 0.001), brushing of child’s teeth (p = 0.003) and swallowing toothpaste (p < 0.001) were related to the prevalence of developmental defects of primary teeth. This study indicated several independent variables which may be related to the prevalence of enamel defects in primary and permanent teeth, but longitudinal studies are required to determine which are causes and which are markers of these developmental defects.
Fluoride-Induced Enhancement of Diffusion in Streptococcal Model Plaque Biofilms
Authors: Rose R.K. , Turner S.J.
Published: April 2003

It has been demonstrated that fluoride decreases the calcium-binding affinity of Streptococcus mutans and approximately doubles the calcium-binding capacity. To investigate the effect of this mechanism on calcium mobility in plaque, 45Ca flux was measured from a condensed films of S. mutans into tracer-free solution. Bacteria were suspended in pH 7.0 or 5.0 buffer including 0, 5, 10, 15 or 20 mmol/l Ca2+ carrier, with or without 5 mmol/l F– and with 45Ca and 3H-inulin. The appearance of 45Ca and 3H-inulin in carrier-containing but initially tracer-free buffer was measured and extracellular fraction (Ve) and bound calcium were calculated. As the ratio (R) of bound to free Ca2+ approached zero at high [Ca2+], the measured diffusion coefficient (rDe) approached the effective diffusion coefficient (De), such that: rDe = De/(1+R). Fluoride increased the rate of calcium diffusion by a reduction in the binding affinity. This work demonstrates that fluoride significantly increases mobility in plaque; this may increase the rate at which calcium is transported between plaque and an underlying lesion and so promote remineralization. This mechanism could also increase the penetration of bacteriocides and suggests a novel method for biofilm treatment.
Brushing Abrasion of Eroded Dentin after Application of Sodium Fluoride Solutions
Authors: Attin Thomas , Zirkel Christoph , Hellwig Elmar
Published: April 2003

The aim of the present in vitro study was to evaluate the influence of sodium fluoride solutions on brushing abrasion of eroded dentin. Dentin specimens were prepared from 60 bovine incisors. The specimens were embedded in acrylic resin, ground flat, polished and subsequently covered with tape exposing an area of 1.8 mm × 10.0 mm in the center of the exposed dentin. The samples were alternatingly stored in a demineralizing solution (5 min) and a remineralizing solution (1 min) for 5 times. The erosive soft drink Sprite light® served as a demineralizing solution and artificial saliva was used as a remineralizing solution. Prior to storage in artificial saliva 15 specimens were each treated for 1 min with 250 and 2,000 ppm fluoride solution, respectively. Fifteen specimens were treated with distilled water instead of the fluoride solution (= eroded controls). The remaining samples were neither eroded with the soft drink nor fluoridated (= uneroded controls). After each immersion in artificial saliva the specimens were submitted to abrasion in a toothbrushing machine. After 5 demineralization-remineralization brushing cycles the total amount of tooth wear due to erosion and subsequent abrasion was profilometrically evaluated. Statistical analysis revealed the significantly lowest wear in the uneroded controls and the highest amount of abrasion in the eroded controls. Application of the fluoride solutions increased the wear resistance of the eroded dentin specimens, showing significantly better protection by the high-concentration compared to the low-concentration solution. The susceptibility to abrasion of the eroded dentin specimens treated with the high-concentration fluoride solution did not differ significantly from the uneroded dentin samples. It is concluded that application of 2,000 ppm sodium fluoride solutions immediately before toothbrushing significantly reduces abrasion of eroded dentin in vitro.
Measurement of Enamel Remineralization Using Microradiography and Confocal Microscopy
Authors: González-Cabezas C. , Fontana M. , Dunipace A.J. , Li Y. , Fischer G.M. , Proskin H.M. , Stookey G.K.
Published: April 2003

Tooth minerals are lost and regained constantly in a normal, human oral environment. Different methods have been developed to measure this gain and loss in enamel minerals; however, these methods deal with different problems, such as being time consuming or involving the use of X–rays. The aim of this study was to determine if remineralization measured in a thin enamel section (TS) by transversal microradiography (MR) can be reliably monitored by measuring lesion parameters (area, total and average dye fluorescence) on the same TS or on half a tooth (HT) with confocal laser scanning microscopy (CLSM). Thirty–six human enamel specimens were demineralized for 96h, and then half of each specimen was covered with an acid–resistant nail varnish. Specimens were divided into three groups (12/group) and subjected for 20 days to a cyclic remineralization regimen with consisted daily of a 4–hour acid challenge, four 1–min treatment periods with 0, 250 or 1,100 ppm F dentifrice slurries (1:2; dentifrice:water) and 20 h in pooled, human saliva, at room temperature. Specimens were cut and analyzed by MR, then stained with a fluorescent dye (0.1mM rhodamine B) for 1 h and analyzed using CLSM. Both MR and CLSM detected significantly greater remineralization (p<0.05) in the specimens treated with the fluoride–containing dentifrices than in the specimens treated with 0 ppm F. Significant differences were detected between specimens treated witht the fluoride–containing dentifrices by MR and CLSM (HT area and total fluorescence). Statistically significant (p<0.05) Pearson correlation coefficients were calculated between the MR and CLSM data: difference in MR mineral content (ΔM) versus HT lesion area = 0.71; ΔM versus HT total fluorescence = 0.70; ΔM versus HT average fluorescence = 0.61; ΔM versus TS lesion area = 0.88; ΔM versus TS total fluorescence = 0.63, and ΔM versus TS average fluorescence = 0.40. It is concluded that confocal microscopy in either TS or HT may provide valid surrogates (area and total fluorescence) for MR measurements in enamel remineralization studies.
In vitro Enamel and Cementum Fluoride Uptake from Three Fluoride–Containing Composites
Authors: Kawai K. , Tantbirojn D. , Kamalawat A.S. , Hasegawa T. , Retief D.H.
Published: April 2003

The incorporation of fluoride into restorations is desirable because of its cariostatic action. The purpose of this study was to determine fluoride release and fluoride uptake by enamel and cementum from three visible light–cured fluoride–containing composites. Seven circular discs of each composite were prepared and the amount of fluoride released into distilled water was determined at daily intervals for 14 days and then after 30, 60 and 90 days. The fluoride concentration in enamel and cementum was determined in three successive depths by an acid etch biopsy procedure. The composite slabs were made and ligated to the enamel and cementum surfaces and the teeth were immersed in synthetic saliva for 7 days. After removal of the composite slabs, three successive biopsies were again performed. Then the teeth were immersed in 1 M KOH for 24 h and similar biopsies done. The fluoride concentrations were adjusted to standardized depths of 10μm, and the total and bound fluoride uptake calculated. The amounts of fluoride released were significantly different among the three composites. The fluoride released decreased sharply after 1 day and then gradually reached a plateau. As for the enamel and cementum fluoride uptake, FluorEver showed the largest uptake followed by FluoroCore and then Pertac–Hybrid.
Litter Effects on Caries in Rats and Implications for Experimental Design
Authors: Raubertas R.F. , Davis B.A. , Bowen W.H. , Pearson S.K. , Watson G.E.
Published: April 2003

The purpose of this study was to obtain quantitative estimates of litter effects on caries development in rats and to examine the implications for design of rat caries experiments. Twelve female Sprague–Dawley rats, aged 60 days, were bred with 4 male rats. Nine of the 12 dams had litters in close proximity. The litters were culled to 10 pups. One pup from each litter was placed with each of the other dams for nursing, leaving 2 pups from each litter with the birth dam. This design allowed the litter effect to be separated into a prenatal component, reflecting the shared genetic makeup and in utero environment of littermates, and a postnatal component reflecting a shared environment from shortly after birth to weaning. Pups were infected with Streptococcus sobrinus and fed Diet 2000 and 10% (w/v) sucrose water for 5 weeks. There was no significant evidence of a postnatal litter effect for smooth surface caries (p = 0.37) or sulcal caries (p = 0.43). The prenatal litter effect was significant for both smooth surface caries and sulcal caries (p<0.01). When litter effects are present, the statistical power of caries studies is improved if animals from the same litter are divided evenly among experimental groups. In addition, if litter effects are present but not allowed for in data analysis, incorrect statistical inferences may be drawn. Based on our results and other reports of litter effects, we recommend planning for litter effects in the design and analysis of rat caries studies.
Digital Radiography of Interproximal Caries: Effect of Different Filters
Authors: Eickholz P. , Kolb I. , Lenhard M. , Hassfeld S. , Staehle H.J.
Published: April 2003

The aim of this study was to compare the effect of different image processing modes (filters) on reproducibility and validity of the assessment of interproximal carious lesions on digitized radiographic images. Standardized radiographs of 34 extracted teeth exhibiting interproximal caries were obtained. All radiographs were digitized and using the FRIACOM–software the central depth (CD) of each carious lesion was measured on the unchanged radiographic image and after use of five different filters with 7fold and 18fold magnification. All measurements were repeated after 1 week to estimate reproducibility. Histometric CD assessments provided a gold standard for comparison with the radiographic measurements (validity). Neither reproducibility nor validity of CD measurements were improved by one of the filters. Measurements of dentinal lesions showed a statistically higher variability than those of enamel lesions (p<0.001). 18fold magnification provided more valid CD measurements than 7fold magnification (p<0.001). In this study digital manipulations of radiographic images failed to result in statistically significantly improved reproducibility or validity of CD measurements.
Effect of Quarterly Treatments with a Chlorhexidine and a Fluoride Varnish on Approximal Caries in Caries–Susceptible Teenagers: A 3–Year Clinical Study
Authors: Petersson L.G. , Magnusson K. , Andersson H. , Almquist B. , Twetmana S.
Published: April 2003

The aim of this study was to compare the effect of two different dental varnishes on approximal caries incidence in teenagers with proven caries susceptibility during a 3–year period. Two hundred 13– to 14–year–old subjects exhibiting at least two approximal enamel caries lesions were selected to take part in the study. One hundred and eighty subjects participated after informed consent and were randomly assigned to two equally sized groups. One group was treated with a fluoride varnish (FV, Fluor Protector) containing 0.1% F every 3rd month and the participants of the other group were treated in the same mode with a chlorhexidine varnish (CV, Cervitec®) containing 1% chlorhexidine and 1% thymol. In total, each subject was treated 12 times during the experimental period. Approximal caries including enamel lesions (DMFSappr) were recorded from four bitewing radiographs exposed at the start and end of the study. The mean (±SD) caries prevalence at baseline was 2.2±3.4 in the FV group and 2.5±4.0 in the CV group. After 3 years, the average approximal caries incidence was 2.7±3.1 and 3.1±3.5 in the FV and CV groups, respectively. The differences at baseline and after 3 years were not statistically significant. In conclusion, treatments every 3rd month with either a fluoride– or a chlorhexidine/thymol–containing varnish showed a promising effect with low approximal caries incidence and progression in teenagers with proven caries suceptibility.
The Effect of Chronic Clonidine Administration on Salivary Glands and Caries in the Rat
Authors: Watson G.E. , Pearson S.K. , Bowen W.H.
Published: April 2003

Clonidine is a widely prescribed, centrally acting antihypertensive with proposed pharmacologic mechanisms of stimulation of central postsynaptic α2–adrenergic receptors and agonist activity at presynaptic α2–adrenergic receptors, interfering with peripheral regulation of norepinephrine and acetylcholine release. Both of these mechanisms are capable of adversely influencing salivary output and composition, potentially leaving an individual with increased caries risk. The purpose of the present study was to determine the effect of chronic administration of clonidine on saliva, salivary glands, and caries in rats. Sprague–Dawley rat pups were infected with Streptococcus sobrinus, given Diet 2000 and 10% sucrose water ad libitum, and either desalivated, or treated with clonidine HCl (125 or 250 μg/kg administered daily for 28 days by means of osmotic minipumps), or assigned as controls. There were no statistical differences in stimulated parotid or submandibular gland salivary output or sublingual gland weights among the groups. The weight of the submandibular glands as a percent of total body weight was significantly decreased in animals that received clonidine when compared with controls. Sulcal caries scores in both clonidine groups and smooth surface caries scores in the high clonidine group were increased when compared with control animals. Positive control animals (desalivated) had significantly higher caries scores than all other groups. These data show that chronic administration of clonidine significantly decreases submandibular gland weight and increases susceptibility to dental caries.
Differences in Acidogenicity of S. sobrinus and S. rattus Are Linked to the Catalytic Efficiency of the Glycolytic Key Enzyme Phosphofructokinase
Authors: Gansser G. , Kneist S. , Stösser L. , Kaufmann M.
Published: April 2003

This contribution describes the biochemical properties of two catalytically different phosphofructokinases (PFKs) purified from Streptococcus rattus LB 2 (PFK–rat) and Streptococcus sobrinus OMZ 65 (PFK–sob), respectively. Steady–state kinetics revealed KM = 0.8 mM for PFK–rat and KM = 0.08 mM for PFK–sob for F–6–P as the substrate. The enzymes also differ in their pH profiles: whereas the highest activity of PFK–rat was measured at pH = 8.0, the optimum pH of PFK–sob was at pH = 7.0. In addition, compared to PFK–sob, PFK–rat was more sensitive against the allosteric inhibitor ATP. PFK catalyzes a committed step of glycolysis, the main acid producing catabolic pathway. Thus, the catalytically more efficient enzyme isolated from S. sobrinus OMZ 65, especially at low pH, could explain the comparably high acidogenicity of this strain.
Caries Rates for the Mesial Surface of the First Permanent Molar and the Distal Surface of the Second Primary Molar from 6 to 12 Years of Age in Sweden
Authors: Mejàre I. , Stenlund H.
Published: April 2003

The aim was to analyse the pattern of caries rates in enamel and dentin of the mesial surface of the first permanent molar (mesial 16,26,36,46; here called 6m) and the distal surface of the second primary molar (distal 55,65,75,85; here called 05d) from 6 to 12 years of age. The material consisted of retrospectively collected bite–wing radiographs of a cohort of 374 children aged 5–7 years at baseline and followed to 11–12 years of age. The following scoring system was used: score 0 = no visible radiolucency, 1–2 = radiolucency in the outer (1) or inner (2) half of the enamel up to the enamel–dentin border, 4 = radiolucency with obvious spread in the outer half of the dentin, and 5 = radiolucency in the inner half of the dentin. Two transitions were used: state 0–2 = the time lapse from state 0 until the lesion had reached state 2, and state 2–4 = the time lapse from state 2 until the lesion had reached state 4 or 5. At the age of 9, the mean defs (decayed, extracted and filled surfaces) of 05d was 0.70 and the mean DFS of 6m was 0.19. The enamel caries rates (state 0–2) were 4.6 new lesions/100 tooth surface–years for 6m and 11.3 for 05d. The dentin caries rates (state 2–4) were 20.5 new lesions/100 tooth surface–years for 6m and 32.6 for 05d. In conclusion, the enamel caries rate for 05d was more than twice that for 6m. Both surfaces had relatively high dentin caries rates, indicating that for these surfaces between 6 and 12 years of age, the rate of progression into the dentin is generally relatively high once the lesion has reached the inner half of the enamel as judged radiographically.
Caries Trends 1992–1998 in Two Low–Fluoride Finnish Towns Formerly with and without Fluoridation
Authors: Seppä L. , Kärkkäinen S. , Hausen H.
Published: April 2003

Water fluoridation in Kuopio, Finland, was stopped at the end of 1992. In our previous study, no increase in caries was found in Kuopio 3 years after the discontinuation of water fluoridation. The aim of the present study was to further observe the occurrence and distribution of caries in Kuopio and Jyväskylä, which was used as the reference town for Kuopio. In 1992, 1995 and 1998 independent random samples of all children aged 3, 6, 9, 12 and 15 years were drawn in Kuopio and Jyväskylä. The total numbers of subjects examined were 688, 1,484 and 1,530 in 1992, 1995 and 1998, respectively. Calibrated dentists registered caries clinically and radiographically. No indication of increasing caries could be found in the previously fluoridated town during 1992–1998. In both towns the mean dmfs and DMFS values either decreased or remained about the same during the observation period. When all study years and both towns were pooled, 25% of the 12– and 15–year–olds with the highest DMFS counts accounted for 79 and 67%, respectively, of all affected surfaces. The mean numbers of fluoride varnish and sealant applications had markedly decreased in 1993–1998 compared to 1990–1992. The fact that no increase in caries was found in Kuopio despite discontinuation of water fluoridation and decrease in preventive procedures suggests that not all of these measures were necessary for each child.
Site–Specific Oral Colonization of Mutans Streptococci Detected by Arbitrarily Primed PCR Fingerprinting
Authors: Grönroos L. , Alaluusua S.
Published: April 2003

The clonal diversity and colonization pattern of mutans streptococci within an individual were studied by using a total of 50 tooth site samples obtained from seven 3– to 7–year–old children. Five children contributed saliva samples. From the 7 subjects, 90, 74, 81, 53, 83, 103, and 114 isolates (a total of 598) representing Streptococcus mutans and Streptococcus sobrinus were included for arbitrarily primed polymerase chain reaction (AP–PCR) fingerprinting. The children harbored one to four different AP–PCR types of mutans streptococci. In 3 of the 7 children, the distribution of AP–PCR types of S. mutans differed depending on tooth site (chi–square test for heterogeneity, p<0.001), suggesting that mutans streptococcal clones may selectively colonize specific hard–tissue sites.
Morphological Study of Cryopreserved Human Corneal Endothelium
Authors: Canals M. , Costa-Vila J. , Potau J.M. , Merindano M.D. , Ruano D.
Published: April 2003

The aim of the present paper is to describe the morphological changes that occur in human corneal endothelium as an immediate consequence of corneal cryopreservation. Therefore, 16 human donor corneas were cryopreserved with an original procedure at a 1 °C/min cooling rate in a freezing solution cryoprotected with 7% dimethylsulphoxide until a final temperature of –100 °C was reached. After storage of the corneas in liquid nitrogen for periods ranging from 1 to 96 days (mean: 34.31 days), the corneas were thawed in a water bath at +37 °C. Eight additional control corneas were processed without cryopreservation. Morphological assessment of the endothelial layer was performed by scanning electron microscopy and trypan blue and alizarin red S vital staining. Results showed cryoinduced damage at variable degrees in all cryopreserved corneas. They were classified into three groups according to the intensity and extension of the cryoinduced damage: group I (n = 10): corneas with minor endothelial alterations consisting in the presence of microholes in the posterior cell membrane; group II (n = 1): corneas with generalized disruption of endothelial intercellular junctions and intact cell membranes; group III (n = 5): corneas with severe endothelial damage consisting of massive cell necrosis and complete alteration of the morphological pattern of the endothelium. All control corneas had intact endothelial layers. Cryoinduced damage cannot be completely avoided with the cryopreservation protocol tested. The high interindividual variability of the results observed is not related to the storage time of the cornea in liquid nitrogen.
Anatomical Variations in the Origin of the Human Ophthalmic Artery with Special Reference to the Cavernous Sinus and Surrounding Meninges
Authors: Matsumura Y. , Nagashima M.
Published: April 2003

The origin of the human ophthalmic artery (OA) and surrounding structures was investigated in 109 cadavers by three different methods: macroscopic, stereomicroscopic, and histological observations. The following results were obtained. (1) Macroscopic observation: In 39% of the specimens the origin of the OA was observable in the cranial cavity and defined as the intradural (ID) type. The other 61% were named the extradural (ED) type. (2) Stereomicroscopic observation: In 59% of the cases, the OA originated from the internal carotid artery over or on the cavernous roof and at least a part of the OA was exposed within the cranial cavity. In the other 41% the OA originated within the cavernous wall or cavity and entered directly the optic dural sheath, thus no part of the OA was visible in the cranial cavity. Therefore, approximately 20% of the origins of the OA might be of the ID type, although they could not be macroscopically identified in the cranial cavity since they might emanate from the internal carotid artery between the optic canal and the optic nerve, even above the cavernous roof. (3) Histological observation: The proximal portion of the OA runs alongside the optic nerve within the subarachnoid space in the cases of the ID type. In contrast, the corresponding portion of the ED type was embedded in the dense fibrous tissue which was continuous both with the dura mater of the cavernous wall and the periosteum of the sphenoid. These anatomical data may provide important information for understanding the variety of the pathology in this region and is also useful for designing operative strategies.
A Rare Anomaly of the Abductor digiti minimi Muscle of the Foot
Authors: Kopuz C. , Tetik S. , Özbenli S.
Published: April 2003

One case with anomalous fascicles in the abductor digiti minimi muscle (ADM), noted in the course of dissecting the left lower extremity of a 62-year-old male cadaver, is described. The ADM had proximally three bellies and distally one. One of the proximal bellies presented the normal belly and others were the supernumerary fascicles. Both fascicles arose from the calcaneus, one was inserted into the base of the fifth metatarsal (FMB) and the other into the tuberosity of the fifth metatarsal (FMT). One belly coursing distally arose from the FMB and was inserted into the proximal phalanx of the fifth digit. The normal belly ended in the FMB and also both in the distal belly and in the flexor digiti minimi muscle. One of the supernumerary fascicles (medial fascicle) crossed the lateral plantar artery. To our knowledge, this is an anatomic variation which has never been described before. The morphology of this anomaly is discussed in relation to previously described anomalies of the plantar muscles.
Immunohistochemical Demonstration of Neuropeptides in the Articular Disk of the Human Temporomandibular Joint
Authors: Haeuchi Yasuko , Matsumoto Ken , Ichikawa Hiroyuki , Maeda Sadaaki
Published: April 2003

The distribution of calcitonin gene-related peptide (CGRP), substance P (SP), vasoactive intestinal polypeptide (VIP) and neuropeptide Y (NPY) was examined in the human temporomandibular articular disk using an indirect immunofluorescent method. All examined neuropeptides were observed in nerve fibers in the disk. These fibers were mostly located in the loose fibrous tissue of the posterior part (posterior attachment) and in the lateral region of the anterior part (anterolateral loose fibrous tissue) of the disk. The posterior attachment and anterolateral loose fibrous tissue occasionally contained isolated nerve fibers which usually showed immunoreactivity (IR) for CGRP or SP. In this tissue, perivascular fibers contained VIP or NPY, whereas isolated fibers and free nerve endings showed the IR for CGRP or SP. These neuropeptides may be involved in the regulation of blood flow and/or pain sensation in the human articular disk of the temporomandibular joint.
The Anatomy of the Angular Branch of the Thoracodorsal Artery
Authors: Seitz Alexander , Papp Stephan , Papp Christoph , Maurer Herbert
Published: April 2003

This study reports an anatomical investigation of the angular branch of the thoracodorsal artery, which can be used in reconstructive surgery to serve as a pedicle for gaining osseous material from the scapula. The study was performed on 135 samples and topography and morphometry of the vessel were investigated. It was found that this artery has five main types of origin. It courses in the fascial gliding layer between the serratus muscle, and the teres major and subscapular muscle to the inferior angle of the scapula. There it provides the bone with blood through periostal branches as part of the arterial rete on the costal and dorsal side of the scapula. The mean length of the angular branch and the thoracodorsal artery together was 148 mm, and when also adding the subscapular artery the overall length became 167 mm. It was found that the length of a pedicle consisting of the angular branch and the thoracodorsal artery is determined by the difference in origin of the vessels with minor influences of the body size. The internal diameters of unfilled fixated vessels measured 3.06 mm for the subscapular, 1.77 mm for the circumflex scapular, 1.30 mm for the thoracodorsal and 0.64 mm for the angular branch. The exact knowledge of the microanatomy in this area is necessary to be able to use the osseous free flap more selectively and have less traumatization in the donor area.
Effect of Matrix Metalloproteinase Inhibitors on Rat Embryo Development in vitro
Authors: Del Bigio Marc R. , Seyoum Girma
Published: April 2003

Matrix metalloproteinases appear to play a role in cell migration and tissue remodeling and are postulated to be important in the development of embryos. We hypothesized that inhibition of these proteinases with the synthetic inhibitor batimastat or with endogenous tissue inhibitor of metalloproteinases (TIMP) would alter in vitro development of day 9 rat embryos. Batimastat had a dose-related effect on embryo growth and viability following 48 h in culture, with significant inhibition at 1.0 μM concentration. Dying cells were observed in many organs of living embryos. TIMP-2 at 3.0 μg/ml had a similar effect on embryo growth. TIMP-1 alone or used in combination with TIMP-2 had no obvious effect. No focal malformations were observed. The effective concentrations are comparable to those which inhibit enzyme activity in cell culture. We conclude that matrix metalloproteinases are probably important in mammalian embryo development.
Establishment of Pluripotent Cell Lines from Vertebrate Species – Present Status and Future Prospects
Authors: Prelle Katja , Vassiliev Ivan M. , Vassilieva Svetlana G. , Wolf Eckhard , Wobus Anna M.
Published: April 2003

Pluripotent embryonic stem (ES) cells are undifferentiated cell lines derived from early embryos and are capable of unlimited undifferentiated proliferation in vitro. They retain the ability to differentiate into all cell types including germ cells in chimeric animals in vivo, and can be induced to form derivatives of all three germ layers in vitro. Mouse ES cells represent one of the most important tools in genetic research. Major applications include the targeted mutation of specific genes by homologous recombination and the discovery of new genes by gene trap strategies. These applications would be of high interest for other model organisms and also for livestock species. However, in spite of tremendous research activities, no proven ES cells colonizing the germ line have been established for vertebrate species other than mouse and chicken thus far. This review summarizes the current status of deriving pluripotent embryonic stem cell lines from vertebrates and recent developments in nuclear transfer technology, which may provide an alternative tool for genetic modification of livestock animals.
Embryonic Stem Cell-Derived Adipogenesis
Authors: Dani Christian
Published: April 2003

Key events leading to terminal differentiation of preadipocytes into adipocytes have been characterized in the recent years. However, master genes that commit progression from multipotent mesenchymal stem cell to the adipoblast stage of development have not yet been identified. The use of embryonic stem (ES) cells as a route to study early events in adipogenesis and to characterize factors involved in the decision of stem cells to follow the adipogenic pathway is described in this paper. The capacity of lif–/– and lifr–/– ES cells to undergo adipocyte differentiation is reported as an application of mutant ES cells to study gene function during the development of adipose cells.
A Role for Epithelial-Mesenchymal Interactions in Tail Growth/Morphogenesis and Chondrogenesis in Embryonic Mice
Authors: Hall Brian K.
Published: April 2003

Neurulation involves development from primary germ layers before any differentiation of embryonic mesenchyme. Subsequently, secondary organogenesis is via epithelial-mesenchymal interaction. It is unclear whether formation of the caudal body axis and tail bud in vertebrate embryos is by temporal and causal extension of primary neurulation, by secondary neurulation, or by secondary induction (epithelial-mesenchymal interactions) as seen in organogenesis of the limb buds, kidneys, heart and other embryonic regions. Reports of a ventral ectodermal ridge (VER) associated with tail bud development in rodent embryos imply that tail bud development may share features with limb bud development, in which the apical ectodermal ridge (AER) directs limb bud outgrowth and skeletal patterning. Organ culture or grafting to the chorioallantoic membranes of host chick embryos, of tail bud mesenchyme with or without tail epithelium, demonstrates that both survival and growth of tail mesenchyme depend on the presence of tail epithelium. Initiation of chondrogenesis of tail mesenchyme was similarly dependent on tail epithelium until 10.5 days of gestation, which is when the VER is at its maximal extent. Initiation of myogenesis was independent of the presence of tail epithelium. These results are discussed in relation to the similarity of tail bud to limb bud developed, and to the different mechanisms employed in differentiation of the cranial and caudal ends of vertebrate embryos. Secondary induction of the caudal body region is argued to be fundamental in vertebrate embryogenesis.
Gross Morphology and Topography of the Adult Intestinal Tract of the Tilapian Fish, Oreochromis niloticus L.
Authors: Smith Bonnie J. , Smith Stephen A. , Tengjaroenkul Bundit , Lawrence Terry A.
Published: April 2003

The intestinal tract of the Nile tilapia, Oreochromis niloticus L., follows a complex course involving multiple loops and coils arranged in a previously undescribed form. From cranial to caudal, five principal regions were identified and designated as the hepatic loop (HL), proximal major coil (PMC), gastric loop (GL), distal major coil (DMC), and terminal segment (TS). The first four of these regions each possessed a reversal flexure and thus could be divided into proximal and distal limbs. Only the terminal segment was straight and undivided. The PMC and DMC were disposed in a spiral, cone-shaped mass (spiral intestine) – their proximal and distal limbs are thus designated as centripetal and centrifugal limbs. These spiral limbs were arranged with each successive limb nested internal to the previous one. Beginning from the stomach, the complete course of the gut including designations of the subdivisions of the major regions was as follows: proximal limb of the HL, distal limb of the HL, centripetal limb of the PMC, centrifugal limb of the PMC, proximal limb of the GL, distal limb of the GL, centripetal limb of the DMC, centrifugal limb of the DMC, and the TS. Though the topographical relations of the various gut loops permitted ready identification of each, external surface features were so similar among the segments that extirpated segments of gut could not be identified as to region of origin. The nesting of successive intestinal loops of the spiral intestine in this fish is novel among patterns previously described, and also among the more intricate of those that have been described.
Immunohistochemical and Ultrastructural Study of Pituitary Folliculostellate Cells during Aging in Rats
Authors: Cónsole G.M. , Jurado S.B. , Riccillo F.L. , Gómez Dumm C.L.A.
Published: April 2003

The impact of aging on pituitary folliculostellate (FS) cells is not well known. The aim of the work reported here was to carry out a quantitative immunohistochemical assessment of the FS population in male and female rats during aging and to correlate the findings with possible changes at the ultrastructural level. Young (4 months), old (20 months) and senescent (29 months) Sprague-Dawley rats of both sexes were sacrificed by rapid decapitation, their pituitaries dissected and processed by both light immunohistochemistry and electron microscopy. Serial sections (4 µm) were obtained at different levels and immunostained by means of rabbit anti-S100 serum as the primary antibody and a peroxidase-mediated EnVision System (Dako). Measurement of volume density (VD) and cell density (CD) was made in S100-reacting elements by means of an image analysis system (Imaging Technology, Optimas). These parameters were found to be significantly (p < 0.05) decreased in old and senescent rats as compared to young animals. In senescent females, which presented a high incidence of microprolactinomas, a significant (p < 0.01) increment of VD and CD was observed in FS cells in the area surrounding the adenomas, together with a marked decrease in those parameters within the tumors. Sexual dimorphism was not found except for the prolactinoma-bearing female group. The ultrastructure of FS cells showed the typical characteristics previously described in the pituitary gland. Only moderate changes in the endoplasmic reticulum were observed in old and senescent animals. We conclude that aging has a clear effect on the morphology of the pituitary FS cell population.
Growth Pattern of the Maxillary Sinus in the Miniature Pig (Sus scrofa)
Authors: Koppe Thomas , Klauke Thomas , Lee SungHee , Schumacher Gert-Horst
Published: April 2003

The biological role of the paranasal sinuses is obscure, can be elucidated through a cross-sectional growth study of the maxillary sinus in miniature pigs. The maxillary sinus area was obtained from lateral cephalograms of left skull halves of 103 female miniature pigs of known ages, from newborn to 24 months. Out of several nonlinear models, the growth of the maxillary sinus was best described with the Gompertz model. The first derivative of the Gompertz curve revealed an increase in the growth rates of the maxillary sinus until 4 months, after which sinus growth slowed down. The eruption of the permanent molars did not seem to have a significant influence on this growth pattern. Furthermore, growth in maxillary sinus size in the miniature pig does not follow growth in skull size closely, which showed the highest growth rates in newborn animals. In addition, a correlation analysis revealed that the relationship between maxillary sinus area and different characteristics of the masticatory apparatus (including linear cranial dimensions, and the dry weight of the masseter and zygomatico-mandibularis muscles) were influenced greatly by skull size. These results suggest that the existence of pneumatic cavities within the mammalian skull is not satisfactorily explained solely by an architectural theory. Epigenetic factors are likely to influence the final shape of the maxillary sinus.
Effect of Mechanical Load on Articular Cartilage Collagen Structure: A Scanning Electron-Microscopic Study
Authors: Kääb Max J. , Ito Keita , Rahn Berton , Clark John M. , Nötzli Hubert P.
Published: April 2003

Little is known about the morphological effect of a mechanical load upon articular cartilage. The objective of this study was to describe and quantify the deformation of the articular cartilage collagen structure of the tibial plateau under static loading. Whole intact rabbit knee joints were loaded in vitro by simulating a quadriceps force of 3×, 1× or 0.5× body weight (high, medium, low) over durations of 30 or 5 min (long, short). Specimens were cryopreserved while under load and prepared for morphological evaluation by field emission scanning electron microscopy. Under high force and long duration loading the collagen fibers exhibited high deformation with an increased thickness of the layer of collagen fibers oriented almost parallel to the surface and a cartilage thickness reduced to 54%. Collagen fiber deformation occurred mostly in the transitional and upper radial zone. The area of tibial indentation and the cartilage thickness reduction increased with magnitude and duration of load. The collagen matrix did show a bulging edge at the border of the meniscus and exhibited remarkable deformation under the meniscus.
Light and Electron Microscopy of the Bulbus arteriosus of the European Eel (Anguilla anguilla)
Authors: Icardo José M. , Colvee Elvira , Cerra Maria C. , Tota Bruno
Published: April 2003

The bulbus arteriosus of teleost fish acts as an elastic reservoir that dilates during ventricular systole to store a large part of the cardiac stroke volume. Despite its functional importance, the knowledge of the structure of the bulbus wall is still fragmentary. We have undertaken a series of studies in order to establish a general morphological plan of the teleost bulbus. The bulbus arteriosus of the European eel is studied here by means of conventional light, and transmission and scanning electron microscopy. The inner surface of the bulbus wall is irregular due to the presence of branching ridges that flatten and disappear toward the ventral aorta. The ridge surface is covered by flattened endocardial cells that show moderately dense bodies. In the ridge tissue, cells near the endocardium are mostly undifferentiated and appear isolated in a loose filamentous matrix. Ridge cells progressively cluster toward the middle layer, become surrounded by a dense matrix, and adopt characteristics typical of smooth muscle cells. This suggests the existence of a differentiation gradient. The middle layer is formed by typical smooth muscle cells embedded in a meshwork matrix that contains thin and thick filaments. Stretching of this meshwork suggests an active role of smooth muscle cells in bulbus wall dynamics. Furthermore, large areas of the extracellular space are occupied by elastin-like material. The amount of this material decreases toward the external layer. Collagen is demonstrated across the entire thickness of the bulbus wall, its amount and organization increasing from the inner toward the outer bulbus surface. The existence of matrix gradients should progressively increase wall strength, maintaining bulbus dilation within safe physiological parameters. The epicardium is formed by flattened cells that contain numerous pinocytotic vesicles, suggesting an active interchange of solutes with the pericardial cavity.
Biosynthesis and Expression of Zona pellucida Glycoproteins in Mammals
Authors: Sinowatz F. , Kölle S. , Töpfer-Petersen E.
Published: April 2003

The zona pellucida (ZP) is an extracellular matrix surrounding the oocyte and the early embryo that exerts several important functions during fertilization and early embryonic development. The ZP of most mammalian species is composed of three glycoproteins (ZPA, ZPB, ZPC), products of the gene families ZPA, ZPB and ZPC that have been found to be highly homologous within mammalian species. Most data on the structure and function of the ZP are obtained from studies in mouse. New data from pig and other domestic animals, however, indicate that the mouse model does not hold for all other species. Whereas in the mouse ZPB is the primary sperm receptor, in the pig ZPA has been shown to possess receptor activity. Contrary to the mouse, where the growing oocyte is the only source of zona glycoproteins, in domestic animals these proteins are expressed in both the oocyte and granulosa cells in a stage-specific pattern and may play also a role in granulosa cell differentiation. In several mammalian species, the epithelial secretory cells of the oviduct synthesize and secrete specific glycoproteins (oviductins) that become closely associated with the ZP of the ovulated oocyte. Once bound to the ZP, oviductin molecules could act as a protective layer around the oocyte and early embryo by virtue of their densely glycosylated mucin-type domains.
Oxidative Stress and Antioxidants in Intestinal Disease
Authors: Thomson A. , Hemphill D. , Jeejeebhoy K.N.
Published: April 2003

Oxidative injury caused by free radicals is an important cause of tissue injury now recognized to occur in inflammation, ischemia and by the action of xenobiotics. It is also recognized to induce gene mutation and promote carcinogenesis. In this review the general concept of nett free radical injury counterbalanced by antioxidants is discussed as oxidative stress. The role of oxidative stress in intestinal ischemia, radiation enteritis, inflammatory bowel disease and the promotion of gastric and colorectal cancer is discussed. The data for the role of oxidative stress in the pathogenesis of ischemic, inflammatory and radiation induced disease are strong, but interventional studies with antioxidants have shown only weak beneficial effects in the above diseases. Therefore the role of antioxidants in the therapy of gastrointestinal diseases remains controversial and should be the subject of controlled trials.
Diagnosis and Management of Appendiceal Mucoceles
Authors: Soweid Assaad M. , Clarkston Wendell K. , Andrus Charles H. , Janney Christine G.
Published: April 2003

Preoperative diagnosis of appendiceal mucoceles is rare. If untreated, one type of mucoceles may rupture producing a potentially fatal entity known as pseudomyxoma peritonei. The importance of diagnosing appendiceal mucoceles is highlighted through a case presentation of a woman who had an incidental finding of mucinous cystadenoma of the appendix during colonoscopic evaluation for occult gastrointestinal bleeding. A detailed review of the medical literature regarding appendiceal mucoceles is presented, with emphasis on the pathologic, clinical, radiologic, and evolving endoscopic features. Surgical options and prognosis are discussed.
Biliary Complications of Orthotopic Liver Transplantation
Authors: Tung Bruce Y. , Kimmey Michael B.
Published: April 2003

Biliary complications are a common cause of morbidity following orthotopic liver transplantation. Complications involving the biliary tree occur after 6–34% of all liver transplants performed, usually within the first 3 months after transplantation. Bile leaks and biliary strictures are the most common biliary complications, but sphincter of Oddi dysfunction, hemobilia, and biliary obstruction from stones, sludge, or casts have also been described. The risk of specific biliary complications is related to the type of biliary reconstruction performed at the time of transplantation. In this article, we review the major types of biliary reconstruction and their associated biliary complications. Specific risk factors for the development of biliary complications are outlined. Finally, the management of biliary complications is discussed, with an emphasis on the role of endoscopic therapy.
Update in Medical Therapy in Inflammatory Bowel Disease: A Clinician’s View
Authors: Katz Seymour
Published: April 2003

Recent advances in the therapy of inflammatory bowel disease specifically directed against the inflammatory and immune mechanisms include an impressive and often overwhelming cornucopia of anti-inflammatory agents, immunomodulators, antibiotics, biologicals, topical therapies, nicotine, heparin, and nutritional supplements. The interface of one drug regimen into another may lead to confounding and often confusing programs of treatment. This review will attempt to offer a perspective of care and an update of specific remedies, but the aim is practicality and usefulness, not encyclopedic detail.
Virtual Colonoscopy: A Gastroenterologist’s Perspective
Authors: Farrell Richard , Morrin Martina , McGee James
Published: April 2003

Virtual colonoscopy is an exciting new imaging technique with potential to alter current diagnostic approaches to colonic diseases, particularly colonic neoplasms. Although colonoscopy continues to offer the highest sensitivity and specificity for evaluation of the colon, virtual colonoscopy may offer greater safety, less discomfort, and consequently greater patient acceptance. In addition, virtual colonoscopy offers shorter procedure time, more accurate lesion location, and potentially lower cost as a screening test. Limited data are currently available to define virtual colonoscopy’s full clinical role. This article describes the technical considerations, current clinical status, limitations, and potential indications of this new and exciting technology which gastroenterologists should not fear but embrace.