bluuebunny/crossref_metadata_2025 huggingface dataset:
Phase II Clinical Trial of Sipatrigine (619C89) by Continuous Infusion in Acute Stroke
Authors: Muir Keith W. , Holzapfel Laurent , Lees Kennedy R.
Published: April 2003

Background: The sodium channel blocker sipatrigine (619C89) prevents ischemia-induced glutamate release and is neuroprotective in animal models of stroke. Previous clinical experience found neuropsychiatric effects attributed to sipatrigine that may have been related to peak plasma concentrations of the drug. Methods: Patients within 12 h of clinically diagnosed stroke were randomized to placebo or sipatrigine at total doses of 10, 18, 27, or 36 mg/kg by continuous intravenous infusion over 65 h. Pharmacokinetic and routine laboratory analyses were undertaken. The outcome at 30 days or 3 months was assessed by Barthel and Rankin scores. Results: Twenty-seven patients were recruited: 7 of 21 patients stopped the sipatrigine infusion early due to adverse events as compared with none of 6 placebo patients. Neuropsychiatric effects (reduced consciousness, agitation, confusion, visual perceptual disturbance, or frank hallucinations) occurred in 16 of 21 patients receiving sipatrigine and in no placebo patients. Nausea, vomiting, infusion site reactions, and hyponatremia were also commoner in sipatrigine patients. Pharmacokinetic parameters were similar to those observed previously. No effects on outcome measures were demonstrated. Conclusions: Continuous infusion of sipatrigine is associated with neuropsychiatric effects. No difference in the nature of these events was evident between this regimen and repeated short infusions, but it was possible to administer higher doses.
Tongue Deviation in Acute Ischaemic Stroke: A Study of Supranuclear Twelfth Cranial Nerve Palsy in 300 Stroke Patients
Authors: Umapathi T. , Venketasubramanian N. , Leck K.J. , Tan C.B. , Lee W.L. , Tjia H.
Published: April 2003

It is generally believed that the supranuclear innervation of the hypoglossal nucleus is bilateral and symmetrical. The aim of this work is to study the frequency and clinical characteristics of supranuclear tongue palsy in unilateral stroke. 300 patients with acute unilateral ischaemic motor strokes (excluding those in the lower brainstem) and an equal number of normal controls were studied for the presence of tongue deviation in a standardised manner. 29% of stroke patients and 5% of controls had tongue deviation (p < 0.00001). Deviation was always to the side of the limb weakness. In patients with a history of stroke, it occurred more frequently in those with previous stroke on the contralateral side. Tongue deviation was most common in patients with clinical features of the non-lacunar stroke subtype (56%) or in those with cortical or large subcortical infarctions on brain CT scan (55 and 45%, respectively). All tongue deviations were associated with supranuclear 7th nerve palsy. Dysphagia and dysarthria occurred in 43 and 90% of patients with tongue deviation. Weakness of the arm was significantly associated with presence of tongue deviation. Tongue deviation in unilateral stroke most likely results from asymmetrical supranuclear control of the 12th cranial nerve in many individuals. The finding that it occurs relatively commonly in large (non-lacunar) infarcts and its association with dysphagia may have clinical utility.
Minority Health Issues and Genetics
Authors: Bowman James E.
Published: April 2003

The Federal government has had many conferences on ethical guidelines involving minorities in research and in genetic testing. Examples of governmental violation of its own ethical precepts will be given with respect to invasion of privacy of employees, dissimulation about the role of abortion in genetic testing, and in sponsoring research abroad that would not be countenanced at home.
Tuned Aperture Computed Tomography and Detection of Recurrent Caries
Authors: Nair M.K. , Tyndall D.A. , Ludlow J.B. , May K.
Published: April 2003

This study compared the diagnostic efficacy of four imaging modalities for the detection of artificially induced recurrent caries: intraoral film, direct digital bitewing images, tuned apertuce computed tomography (TACTTM) slices and iteratively restored TACTTM images using an in vitro model. Twenty-four posterior teeth were prepared for MOD inlay restorations. These were then restored with different restorative materials (amalgam, Herculite and Durafill). Lesions were simulated in half the number of surfaces studied. These lesions were created either at the intersection of the facial or lingual walls and the gingival floor or on the gingival floor midway between the facial and lingual walls in the proximal boxes of the MOD restorations. Analysis of observations from 8 observers using ROC curve reveal the superior diagnostic efficacy with TACTTM iteratively restored images (Az for TACTTM iteratively restored images = 0.9171, TACTTM slices = 0.7052, Film = 0.6608, direct digital images = 0.5979). ANOVA revealed significance with respect to the imaging modality used (p < 0.0001). The results suggest that TACTTM images hold promise as a more effective imaging modality than film or direct digital systems for detection of recurrent caries.
Prolonged Demand Breast-Feeding and Nursing Caries
Authors: Weerheijm K.L. , Uyttendaele-Speybrouck B.  F.  M. , Euwe H.C. , Groen H.J.
Published: April 2003

The aim of this study was to study the characteristics and to explore risk factors within a group of Dutch children breast-fed on demand over a prolonged period, whose mothers attended the meetings of La Leche League. Ninety-six children, 55 boys and 41 girls (mean age 28.8 months, SD 8.8), were examined. Most of the parents belong to a higher socio-economic working class. The examination included a questionnaire and dietary sheet, combined with the caries status of the child. On average the children were breast-feed for 21.5 months (SD 9.8). The mean age at which the parents started brushing the children’s teeth was 11.7 months (SD 5.1). Fluoridated toothpaste (250 ppm fluoride) was used by 70% of the children. The children were divided into three groups according to their caries pattern: 1 caries-free; 2 caries, and 3 nursing caries. Dentine caries was found in 14 (14.5%) of the children, of which 9 (9.3%) met the criteria of nursing caries. The mean dmfs of all children examined was 1.2 (SD 4.8). Up to 18 months of age the breast was given significantly more frequently during the night and up to 24 months during the day time, to the children of the nursing caries group compared to the children in the other two groups. The children still being breast-fed at the time of investigation more frequently slept in their parents’ bed. The children of the nursing-caries group used fluoridated dentifrices less often. The majority of children of the caries and nursing-caries groups did not receive fluoride from other sources. The results of the present study demonstrate that prolonged demand breast-feeding does not lead to a higher caries prevalence although comparison between the groups demonstrates that frequent breast-feeding and low additional fluoride use should be considered as contributing factors in the process of nursing caries.
The Isolation of Actinomyces naeslundii from Sound Root Surfaces and Root Carious Lesions
Authors: Brailsford S.R. , Lynch E.J.R. , Beighton D.
Published: April 2003

The isolation of Actinomyces naeslundii from sound, exposed root surfaces (n = 56) and soft and leathery root carious lesions (n = 71) was investigated. Root carious lesions were sampled after the removal of overlying plaque. Supragingival plaque or carious dentine was sampled using a sterile excavator, the samples were disaggregated and cultured on both selective and non-selective media. A. naeslundii isolates were identified to the genospecies using specific antisera. Significantly greater numbers and proportions of A. naeslundii genospecies 2 than A. naeslundii genospecies 1 were isolated from all sites sampled. There was no significant difference between the numbers and proportions of the two genospecies isolated from leathery and soft lesions. The relationship between the presence of A. naeslundii genospecies and aciduric and acidogenic organisms was investigated. Those sound exposed root surfaces from which A. naeslundii genospecies 1 and/or 2 were isolated yielded significantly lower numbers of lactobacilli and yeasts than the surfaces from which A. naeslundii were not isolated. This difference was also found in leathery lesions but not soft root carious lesions. The microflora of soft root carious lesions was found to comprise primarily gram-positive pleomorphic rods which formed 70±7.8% of the flora, while in plaque from exposed root surfaces and in infected dentine from leathery lesions the gram-positive pleomorphic rods represented only 35% of the flora.
Reliability of Visual Examination, Fibre-Optic Transillumination, and Bite-Wing Radiography, and Reproducibility of Direct Visual Examination Following Tooth Separation for the Identification of Cavitated Carious Lesions in Contacting Approximal Surfaces
Authors: Hintze H. , Wenzel A. , Danielsen B. , Nyvad B.
Published: April 2003

The aim of this study was to evaluate the diagnostic accuracy of visual, fibre-optic transillumination (FOTI), and bite-wing radiographic examination performed by 4 observers for the identification of cavitated carious lesions in contacting approximal surfaces, and to assess the inter-observer agreement with these methods and with direct visual examination conducted after tooth separation, the method used as validation for definitive determination of cavitation. A total of 338 unrestored approximal surfaces in 53 students were examined independently by 4 dentists using the diagnostic methods under study. The results from the diagnostic methods were compared with the results from the validation method for each observer. The sensitivities for identification of cavitated lesions using visual examination ranged from 0.12 to 0.50. For FOTI and radiography, the sensitivities ranged from 0.00 to 0.08 and from 0.56 to 0.69, respectively. The specificities exceeded 0.90 for all observers with all methods. Kappa values expressing inter-observer reproducibility were lowest for FOTI, followed by visual and radiographic examination. On the basis of these results, it was concluded that FOTI was the least reliable of the diagnostic methods tested. For the validation method, the inter-observer agreement was only ‘substantial’. This implies that the method cannot be used as a validation for other diagnostic methods applied for the identification of cavitated carious lesions in contacting approximal surfaces. However, visual inspection after tooth separation may serve as a supplementary diagnostic tool to conventional visual and radiographic examination for clinical management of aproximal carious lesions.
Incidence and Progression of Approximal Caries from 11 to 22 Years of Age in Sweden: A Prospective Radiographic Study
Authors: Mejàre I. , Källestål C. , Stenlund H.
Published: April 2003

Using annual bite–wing radiographs, the incidence and progression of approximal caries (4d–7m) were assessed longitudinally in teenagers and adolescents whose treatment had been based on remineralizing rather than restorative strategies. A closed cohort of 536 children initially was followed from 11 to 22 years of age. The scoring system was: 0 = no visible radiolucency; 1–2 = radiolucency in the enamel up to the enamel–dentin border; 3 = radiolucency with a broken enamel–dentin border but with no obvious progression in the dentin; 4 = radiolucency with obvious spread in the outer half of the dentin, and 5 = radiolucency in the inner half of the dentin. Caries rates were estimated as the number of new lesions/100 tooth surface–years, and the Kaplan–Meier estimate was used to calculate the cumulative survival time of each approximal surface. Three events were used: the transitions from states 0 to 2, 2 to 4 and 3 to 4. The results showed a considerable variation between the surfaces in both caries rates and survival time. For all surfaces combined, the median caries rate from state 0 to 2 was 3.9 new lesions/100 tooth surface–years; from state 2 to 4, the rate was 5.4, and from state 3 to 4 it was 20.3. Of the sound surfaces (state 0), 75% survived 6.3 years without reaching state 2. Given state 2, 75% survived 4.8 years without reaching the outer half of the dentin (state 4), while given a lesion at the enamel–dentin border (state 3), 75% survived 1.3 years without doing the same. The median survival time of lesions from state 3 to 4 was 3.1 years. The group with DMFSappr>1 at the age of 11–12 years had a risk of new approximal enamel lesions (state 0–2) that was 2.5 times greater than that of the group with DMFSappr = 0–1.
Dental Caries, Sugar–Eating Habits and Toothbrushing in Groups of 4–Year–Old Children 1967–1997 in the City of Umeå, Sweden
Authors: Stecksén-Blicks C. , Borssén E.
Published: April 2003

Four–year–old children in the city of Umeå, northern Sweden, have been the subjects for studies of dental caries at regular intervals between 1967 and 1997. Similar methods and criteria were used in all studies and the children were selected from the same catchment areas. The results of this study signified a shift in the trend towards a declining caries prevalence among 4–year–old children. There was a slight non–significant increase in the number of children with caries as well as in the mean dmft and dmfs values between 1992 and 1997. The mean dmfs value was 7.8 in 1967 and declined to 4.5 in 1971. It was 2.9 in 1976 and 2.0 in 1980 and 1987, 1.8 in 1992 and increased to 2.0 in 1997. Ten percent of the children were immigrant or refugee children in 1997 compared to 6% in 1992 and they had a significantly higher caries prevalence than children with a Swedish background (p<0.001). In 1997, 58% of the children had one or more daily intakes of sugary snacks such as buns, cakes sweets, soft drinks, etc. There was an increasing consumption of sweets and soft drinks between 1987 and 1997.
Inhibitory Effects of Oolong Tea Extract on Caries–Inducing Properties of Mutans Streptococci
Authors: Matsumoto M. , Minami T. , Sasaki H. , Sobue S. , Hamada S. , Ooshima T.
Published: April 2003

The inhibitory effects of oolong tea extract (OTE) on the caries–inducing properties of mutans streptococci were examined in vitro. OTE reduced the rate of acid production by mutans streptococci accompanied with the retardation of growth rate of mutans streptococci, while the action by chromatographically isolated oolong tea polyphenol (OTF6) was weak. On the other hand, both oolong tea products decreased cell surface hydrophobicity of almost all the oral streptococci examined in the present study, and also induced cellular aggregation of Streptococcus mutans, Streptococcus oralis, Streptococcus sanguis or Streptococcus gordonii. In these reactions, OTF6 showed a more pronounced activity than OTE. Furthermore, the oolong tea products inhibited the adherence of mutans streptococci to saliva–coated hydroxyapatite. These results suggest that OTF6 may inhibit bacterial adherence to the tooth surfaces by reducing the hydrophobicity of mutans streptococci, and OTE may inhibit caries–inducing activity of mutans streptococci by reducing the rate of acid production.
The Effects of Milk and Kappa–Casein on Salivary Pellicle Formed on Hydroxyapatite Discs in situ
Authors: Vacca Smith A.M. , Bowen W.H.
Published: April 2003

The effects of milk and κ–casein rinses on the salivary pellicle formed on hydroxyapatite discs carried in the mouth were studied. SDS–PAGE analyses revealed an increase in the number of proteins deposited onto the discs carried after the water and milk rinses only. Scanning electron microscopy studies revealed the deposition of an amorphous material, small, micelle–like structures, cocci and rods on discs carried in the mouth after the water rinse. Large, micelle–like structures were seen on discs carried in the mouth after the milk and κ–casein rinses; bacteria were not seen. Glucosyltransferase (Gtf) activity on discs carried in the mouth after the milk and κ–casein rinses were 45±5 and 67±2% lower than the activity of Gtf on discs carried in the mouth after a water rinse, respectively. These data suggest that milk and κ–casein may influence pellicle formation in vivo.
Twenty–Four Month Coronal Caries Incidence: The Role of Dental Care and Race
Authors: Gilbert G.H. , Foerster U. , Dolan T.A. , Duncan R.P. , Ringelberg M.L.
Published: April 2003

Objectives: To describe for a diverse sample of dentate middle–aged and older adults: (1) the 24–month incidence of coronal caries, and (2) its association with a broad range of clinical, behavioral, financial, attitudinal, and sociodemographic factors. Methods: The Florida Dental Care Study is a prospective observational longitudinal cohort study of 873 persons who at baseline had at least 1 tooth and were 45 years or older. In–person interviews and clinical examinations were conducted at baseline and 24 months, with 6–monthly telephone interviews between those times. A multinomial logistic regression was done to predict whether a participant was in one of four mutually exclusive groups at the 24–month examination (new decay only [NDO]; new filling(s) only [NFO]; both new decay and filling(s) [BOTH]; or neither [NONE]). Results: Only 33% of the 24–month participants were in the NONE group. There was no significant difference in caries incidence between regular attenders and problem–oriented attenders, regardless of whether teeth crowned at baseline, incident crowns, or incident root fragments were excluded. However, once differences in incident tooth loss and baseline clinical, behavioral, financial, and attitudinal differences were taken into account, regular attenders did appear to benefit by developing fewer coronal lesions and fewer dental symptoms than problem–oriented attenders. Baseline carious surfaces, filled surfaces, number of teeth, and bulk restoration fractures predicted caries incidence, but baseline cusp fractures did not. Persons with negative dental attitudes were more likely to be in the NDO and BOTH groups, and negative attitude toward brushing and flossing (but not their frequency) also predicted caries incidence. Conclusion: Certain baseline clinical conditions, approach to dental care, ability to pay for dental care, dental attitudes, race, and age group were predictive of coronal caries incidence, and regular attenders appeared to benefit from regular attendance.
Binding Characteristics of Streptococcus mutans for Calcium and Casein Phosphopeptide
Authors: Rose R.K.
Published: April 2003

Casein phosphopeptides (CPP) stabilize amorphous calcium phosphate (ACP) and may be used to localize ACP in dental plaque, maintaining a state of supersaturation with respect to tooth enamel, reducing demineralization and enhancing remineralization [Reynolds, J Dent Res 1997;76:1587–1595]. The aim of this paper is to investigate these effects by measuring the affinity and capacity of Streptococcus mutans for CPP–ACP. Using the equlibrium dialysis system described by Rose and Hogg [Biochim Biophys Acta 1995;1245:94–98], assessment of calcium binding by a plaque streptococcus at a fixed CPP–ACP concentration gives a series of CPP–ACP–influenced dissociation constants for calcium. These data can then be used to derive a true dissociation constant for CPP–ACP itself. The results demonstrate that CPP–ACP binds with about twice the affinity of the bacterial cells for calcium up to a value of 0.16 g/g wet weight cells. Application of CPP–ACP to plaque may cause a transient rise in plaque fluid free calcium which may assist remineralization. Subsequently, CPP–ACP will form a source of readily available calcium to inhibit demineralization. Hence, CPP–ACP binds well to plaque, providing a large calcium reservoir, which is likely to restrict mineral loss during a cariogenic episode and provide a potential source of calcium for subsequent remineralization. Overall, once in place, CPP–ACP will restrict the caries process.
The Mechanism of Growth-Promoting Effects of Prolactin in Embryogenesis – Links to Growth Factors
Authors: Karabulut A.K. , Layfield R. , Pratten M.K.
Published: April 2003

The polypeptide hormone prolactin (PRL) has been implicated in the regulation of embryonic growth and development, but the control mechanisms involved in the effects of the hormone are poorly understood. Several investigators suggested that there may be a possible link between the effects of PRL and insulin-like growth factors (IGFs). Recent studies have also shown that ligand-induced activation of PRL receptors leads to tyrosine phosphorylation of multiple intracellular proteins, and tyrosine kinase activation takes place in mediating the mitogenic action of PRL. In order to determine whether IGFs are involved in mediating the growth-promoting effect of PRL, rat embryos were culture in vitro for 48 h in whole rat serum and serum depleted of low molecular weight molecules (30 kD retenate) supplemented with rat PRL in the presence and absence of antisera against rat PRL, IGF I and IGF II. To investigate the effects of inhibiting the signal transduction of the PRL receptors, the embryos were preincubated for 2 h in retenate in the presence of tyrosine kinase inhibitors, tyrphostin 47 and genistein, then rat PRL was added to the culture medium. Embryos cultured in retenate showed severe growth retardation, and the addition of rat PRL caused significant increase in growth and development of the embryos suggesting that embryos may be able to utilize maternally derived PRL during organogenesis. The presence of antiserum against rat PRL abolished the PRL-induced increase in development and antibodies against IGF I and II had a similar effect, suggesting that IGFs may be involved in the effect of the hormone. The 2-hour preincubation with genistein and tyrphostin also abolished the PRL-induced increase in development. These results indicate that functional PRL receptors are present in rat embryos at this stage which may play an important role in the control of growth and development and this may be linked to growth factors and their receptors.
Comparison of Amounts and Properties of Collagen and Proteoglycans in Condylar, Costal and Nasal Cartilages
Authors: Pietilä K. , Kantomaa T. , Pirttiniemi P. , Poikela A.
Published: April 2003

In this study we compared the compositions of extracellular matrices of condylar, costal and nasal cartilages to characterize differences in growth patterns in relation to matrix composition. Condylar, costal and nasal cartilages of 25- and 35-day-old rabbits were extracted and subjected to bio- and histochemical analysis to determine total amounts of collagen and amounts and aggregating properties of proteoglycans. We found that proteoglycan content and aggregate formation were greatest in nasal cartilage, and lower in costal and markedly lower in condylar cartilage. The amount of proteoglycans increased by varying amounts in all samples with age. Collagen content was highest in costal cartilage. In 25-day-old rabbits the quantity of collagen in condylar cartilage exceeded that in nasal cartilage. In 35-day-old rabbits the quantities were nearly the same. It is suggested that collagen does not only provide tensile strength, but counteracts forces responsible for interstitial growth such as osmotic pressure. Based on the results, it seems that the amount of proteoglycans is greater in cartilages, which have greater independent growth potential. Variations in increase in amount of proteoglycans with age could reflect differences in the timing of growth of such cartilages.
Early Development of the Müllerian Duct in Avian Embryos with Reference to the Human
Authors: Jacob M. , Konrad K. , Jacob H.J.
Published: April 2003

In vertebrates, the female reproductive system arises from the Müllerian (paramesonephric) duct which develops in both sexes under the influence of the Wolffian (mesonephric) duct. For a better understanding of the interactions between the Müllerian duct and its adjacent tissues, we present a systematic scanning and transmission electron microscopic investigation of early stages of avian Müllerian duct development. This starts within the cranial part of the Müllerian ridge from a placode-like thickening and deepening of the coelomic epithelium containing nephrostomes as remnants of the last pronephric and first mesonephric tubules. Groups of cells detach from this placode and rapidly expand caudally as a solid cord. This becomes canalized, but the tip region remains mesenchymal and is found enclosed within the basal lamina of the Wolffian duct. Immunostaining reveals that the Müllerian duct migrates within a matrix rich in laminin and entactin. When the canalized duct has opened into the coelomic cavity, one or more secondary ducts are found immediately caudal of the main funnel, for a short period only, possibly to supply material to the expanding duct. BrdU-anti-BrdU reaction reveals a high proliferation of the duct epithelium. The thickened epithelium of the Müllerian ridge dissolves to form the mesenchymal layers of the duct. Immunostaining with vimentin argues against a cellular contribution of Wolffian duct cells to the Müllerian duct. Comparing the data from avian embryos with those of human indicates that the modalities of early Müllerian duct development are similar in both species.
Three-Dimensional Visualization and Quantification of the Mandibular Articular Surface by Optical Profilometry
Authors: Dirksen D. , Stratmann U. , Kleinheinz J. , von Bally G. , Bollmann F.
Published: April 2003

The aim of this study was to introduce a nondestructive optical technique for the quantitative assessment of natural biological surfaces as demonstrated with the example of the articular surface of the human temporomandibular joint. The computer-assisted quantitative evaluation of the surface is realized by the aquisition of three-dimensional images via the optical technique of phase measuring profilometry. After mathematical processing of the data set the resulting image can be visualized as three-dimensional object surface reconstructions or as grid surfaces from which arbitrary sections may easily be extracted. From such single sections we can calculate a value that represents the degree of height deviations of the section profile and can be regarded as a parameter for the surface roughness. Further quantitative information about the surface topography is provided by the Fourier transform analysis of the profiles. The Fourier spectrum contains information about the spatial distribution of roughness-causing protuberances along the overall surface. As an example one healthy condyle and one remodeled condyle from macerated cadaver mandibles were investigated. For the two samples evaluated we calculated a mean surface roughness of the entire articular surface with a value of 0.03 ± 0.005 mm for the healthy condyle with its smooth surface and a value of 0.14 ± 0.009 mm for the remodeled condyle. We recommend optical profilometry as a sophisticated technique for a more objective and quantitative pathological classification of articular surfaces and similar objects.
Rat Model of Achilles Tendon Disorder
Authors: Messner Karola , Wei Yuzhi , Andersson Britt , Gillquist Jan , Räsänen Tuomas
Published: April 2003

Three-month-old male rats were subjected 3 times weekly for 1 h to eccentric exercise of one triceps surae muscle (30 stimulations/min) under general anesthesia in order to induce Achilles tendon disorder corresponding to paratenonitis and tendinosis in man. Net muscle work during the sessions ranged between 0.67 and 4.37 mJ (mean 1.72, SD 0.77). After 9 and 13 sessions, respectively, 2 rats started to show gait alterations during the functional test which was performed 2–3 times weekly. These rats were killed after additional sessions which showed a worsening of the limp. The other trained rats and controls did not limp and were killed after 7–11 weeks. Histologic evaluation of the Achilles tendons from the exercised limb showed in the majority of the cases hypervascularization, increased number of nerve filaments and increased immunoreactivity for substance P and calcitonin gene-related peptide. The tendons from the nonstimulated limb looked normal. The distribution of collagen types I and II appeared normal in the tendon and its insertion to the calcaneus. Inflammation of the epi- and paratenon could be provoked in the rat, but tendon changes corresponding to chronic tendinosis did not develop within 11 weeks with the used training regime. The clinical relevance of this model for chronic tendon disease needs to be evaluated further.
Nuclear Morphologies of Bovine Corneal Cells as Visualized by Confocal Microscopy
Authors: Lwigale Peter Y.
Published: April 2003

Confocal laser scanning microscopy was used to characterize nuclear morphology of the three cell layers of bovine cornea in vivo. Corneas fixed with formalin were stained with propidium iodide, whereas living cells in nonfixed corneas were stained with PicoGreen. Nuclei in the three corneal cell layers consistently assume strikingly different shapes. Round nuclei were observed throughout the layers of the epithelium of both fixed and living cells. Stromal fibroblasts (keratocytes) showed approximately equal numbers of elliptical and bean-shaped nuclei arrayed in a variety of orientations. Keratocytes near Bowman’s layer had almost round nuclei whereas those near Descemet’s membrane had more elongated elliptical nuclei. Lobulate nuclei arranged in a regular pattern were observed throughout the endothelium. Some of the lobulate nuclei were large and stained less intensely with the fluorescent dyes. In addition, keratocytes in vitro displayed the same two distinct nuclear morphologies as in vivo. These observations indicate that each cell layer of the cornea contains nuclei with characteristic morphologies and that, in the case of keratocytes, the cells maintain their characteristic nuclear morphologies in vitro.
Establishment of Ionic Channels and Signalling Cascades in the Embryonic Stem Cell-Derived Primitive Endoderm and Cardiovascular System
Authors: Hescheler J. , Fleischmann B.K. , Wartenberg M. , Bloch W. , Kolossov E. , Ji G. , Addicks K. , Sauer H.
Published: April 2003

The first organ system to be established in early embryogenesis is the cardiovascular system which develops upon interaction with hypoblastic cells of the primitive endoderm. Here we focus on recent work on embryoid bodies derived from pluripotent embryonic stem (ES) cells. Ca2+ oscillations and Ca2+ signalling pathways during the differentiation of primitive endodermal cell layers are reported. Furthermore, the development-dependent expression of ion channels and the buildup of signalling cascades involved in the modulation of voltage-dependent L-type Ca2+ channels during early cardiomyogenesis and the formation of functional vascular structures in the process of vasculogenesis and angiogenesis are reviewed. We also report on the use of green fluorescent protein reporter gene expression under the control of cardiac-specific promoters, e.g. the human cardiac α-actin promoter, which enables the identification and in vivo characterization of cardiomyocytes at very early stages of cardiomyogenesis.
Caroticotympanic Artery: Anatomically a Normal Branch or a Variation of the Internal Carotid Artery?
Authors: Andreo Jesus Carlos , Caldas Navarro João Adolfo , Toledo Filho João Lopes , de Araújo José Carlos
Published: April 2003

Most investigators consider the caroticotympanic artery to be a normal branch of the petrous portion of the internal carotid artery, although some authors disagree. The present study was conducted on forty human temporal bones removed from adult cadavers of both sexes. Twenty pieces were injected and dissected under a surgical microscope, 10 pieces were injected and submitted to corrosion, and 10 were injected and diaphanized in order to observe the frequency of the caroticotympanic artery in the petrous portion of the internal carotid artery. The caroticotympanic artery was not observed in any of the pieces submitted to microdissection and was observed in only 1 of the pieces (10%) submitted to corrosion and also in 1 of the diaphanized pieces (10%). In both cases, only one artery was present. Based on the present results showing that the rate of occurrence of the caroticotympanic artery was very low by the three techniques utilized (microdissection 0%; corrosion 10%; diaphanization 10%), it is possible to conclude that, anatomically, the artery should be considered as a variation and not as a normal branch of the petrous portion of the internal carotid artery, in agreement with most literature reports.
The Sinus Hair Follicle of the Cat
Authors: Gasse H. , Schwarz R.
Published: April 2003

The cat’s sinus hair follicle is described histologically with special regard to structural characteristics and functional mechanisms of sinus hair growth and sinus hair cycle. Special features of both cornification of the inner epithelial root sheath and hair fixation, respectively, result in a loss of traction that is required for hair growth and hair expulsion. Instead, there is the outgrowing new anagen sinus hair that pushes the preceeding sinus hair upwards, and – secondly – there is a long-lasting cell pro- liferation. Cell proliferation – immunocytochemically detected with anti-proliferating cell nuclear antigen – continues in the preceeding sinus hair while the formation of a new, succeeding sinus hair follicle begins. No distinct, ‘typical’ catagen state of sinus hair follicle has been found even in a large number of collected specimens. These findings stress that the well known features of hair growth and hair cycle in the pelage hair follicle cannot be generalized and adopted in all details to the sinus hair follicle.
Three-Dimensional Organization of Microtubules in Tumor Cells Studied by Confocal Laser Scanning Microscopy and Computer-Assisted Deconvolution and Image Reconstruction
Authors: Strohmaier Anja-Rose , Porwol Torsten , Acker Helmut , Spiess Eberhard
Published: April 2003

Confocal microscopy, image deconvolution and computer-assisted methods have been used to reconstruct the three-dimensional (3-D) distribution of tubulin in cells. The techniques were applied to tumor cells growing under regular culture conditions (planar cultivation) and those penetrating into reconstituted collagen matrices (spatial cultivation). As expected the application of deconvolution algorithms enhanced the resolution of results. The deconvolution using the maximum likelihood estimation included the measurement of the point spread function of the optical setup. The data visualization of the resulting data sets uses volume as well as surface rendering approaches. The 3-D reconstruction gives a clear image of the spatial arrangement of tubulin fibers in relation to cell shape and position of other cellular organelles, particularly the nucleus. The tubulin forms an intricate network of fibers of variable thickness. The highest tubulin concentrations appear in the cell periphery and particularly in pseudopodia/invadopodia. This is indicative of an enhanced transport of intracellular material facilitating cell movement and lysis of the extracellular matrix. The investigation is assumed to stimulate further experiments using a variety of techniques leading to the complete understanding of the spatial architecture of living cells.
Differentiation of Myoblasts in Serum-Free Media: Effects of Modified Media Are Cell Line-Specific
Authors: Lawson Moira A. , Purslow Peter P.
Published: April 2003

Myoblast cell lines are grown and differentiated readily in cell culture. Two cell lines typically used for investigating the growth and differentiation of muscle are the mouse cell line C2C12 and the rat cell line L6. The differentiation of these cells in vitro requires a switch from a serum-rich medium to a less rich medium after the cells have reached confluence. Since the components present in serum are not well characterized, the use of a better defined medium for these studies was investigated. C2C12 and L6 myoblasts were differentiated in both serum-containing and serum-free media. The differentiation state of these cultures was then tested both microscopically and biochemically. Cultures were checked for myotube formation, the activity of creatine phosphokinase and the presence of sarcomeric actin. In C2C12 cells, the extent of differentiation was greater in the serum-free than in the serum-containing system. In both media types, the C2C12 cells produced sarcomeric actin, showing the presence of sarcomere structure in the myotubes. In L6 cells, however, myotubes were readily formed in medium containing 2% horse serum, but not in the serum-free system. In addition, the ability of C2C12 cells to differentiate on substrates coated with extracellular matrix proteins was shown to be media-dependent. The presence of extracellular matrix proteins did not enable L6 cells to form myotubes when cultured in serum-free media. Primary cultures of chick myoblasts were able to differentiate in both media tested, with Dulbecco’s modified Eagle medium containing horse serum being a more efficient medium for cell fusion. This study shows a divergence in muscle cell line responses in three cell lines, two of which are typically used as ‘model systems’ for understanding muscle growth and development.
Development of Chick Cardiomyocytes: Modulation of Intermediate Filaments by Basic Fibroblast and Platelet-Derived Growth Factors
Authors: Vélez Celia , Aránega Amelia E. , Marchal Juan A. , Melguizo Consolación , Prados Jose-Carlos , Carrillo Esmeralda , Aránega Antonia
Published: April 2003

Recent studies suggest that peptide growth factors play a functional role in cardiac muscle. To test whether embryonic cardiac muscle is a target for regulation by basic fibroblast growth factor and platelet-derived growth factor, we analyzed the effects of these peptides on the expression of the intermediate filaments desmin and vimentin at the subcellular level during development. Sodium dodecyl sulfate-gel electrophoresis, immunoblotting and fluorescence-activated cell sorting analysis were used to study the effect of basic fibroblast growth factor and platelet-derived growth factor on cultures of chick cardiomyocytes during development. Cytoplasmic and cytoskeletal concentrations of desmin and vimentin were dependent on the stage of embryonic development and on the type of growth factor added to the culture. The most significant finding was the increase in desmin expression in the cytoplasmic and cytoskeletal compartments after treatment with basic fibroblast growth factor (10 ng/ml) of chick heart cells at Hamburger and Hamilton stage 19. In more mature stages, basic fibroblast growth factor did not modify the levels of desmin expression. However, this factor led to a progressive deceleration in the rate of increase in vimentin expression. Platelet-derived growth factor increased vimentin expression in all stages studied, the greatest increases appearing in early stages of heart development. Our findings support the hypothesis that basic fibroblast growth factor plays a role in cardiomyocyte differentiation during the early stages of development, whereas platelet-derived growth factor has a dedifferentiating effect.
Muscle Sizes and Moment Arms of Rotator Cuff Muscles Determined by Magnetic Resonance Imaging
Authors: Juul-Kristensen B. , Bojsen-Møller F. , Finsen L. , Eriksson J. , Johansson G. , Ståhlberg F. , Ekdahl C.
Published: April 2003

Biomechanical models which require information on, e.g., joint torque and muscle force are useful in the estimation of when and how mechanical overload of the musculoskeletal system may lead to disorders. The aim was to study the reliability and validity of magnetic resonance imaging (MRI) to quantify muscle sizes and moment arms by MRI and to test selected anthropometric measures as predictors of muscle sizes and moment arms. A total of 20 healthy Scandinavian women (age 22–58 years) participated in an MRI scanning of their dominant shoulder. With a PC-based program the reliability and the validity of the MRI measurements was estimated to be high, and mean anatomical cross-sectional areas (ACSA) and muscle lengths were measured to be 4.0, 9.8 and 12.1 cm2 and 12.0, 12.6 and 12.8 cm for m. supraspinatus, m. infraspinatus and m. subscapularis, respectively. Volumes were calculated to be 48.8, 125.1 and 153.6 cm3. Moment arms were measured with the upper arm in a neutral position and in a functional position of 34° abduction for m. supraspinatus only, and were 2.4 and 2.6 cm. Physiological cross-sectional area (PCSA) and its fiber force component were estimated from dissected fiber length and pennation angle. MRI volume and PCSA were 1.4–1.7 times higher than dissection data, primarily because of age differences. No external anthropometric measures were found to be predictors of volumes or moment arms.
Localization of P2X Receptors in the Guinea Pig Adrenal Gland
Authors: Afework Mekbeb , Burnstock Geoffrey
Published: April 2003

The distribution of each of the seven subtypes of adenosine 5′-triphosphate (ATP)-gated P2X receptors was investigated in the adrenal gland of guinea pig utilizing immunohistochemical techniques. The occurrence of positive immunoreactivity with specific distribution was observed for antibodies against P2X1, P2X2, P2X5 and P2X6 receptors, whereas no immunoreactivity was found for antibodies against P2X3, P2X4 and P2X7 receptors. Immunoreactivity for P2X1 occurred in cells of the inner region of the zona reticularis of the cortex, Several P2X2-immunoreactive connective tissue-like elements were located between groups of cortical cells of the zona reticularis. Bundles and terminals of nerve fibres as well as intrinsic neurones gave positive immunoreactivity for P2X5. The immunoreactive nerve fibres appeared to belong to both extrinsic preganglionic sympathetic and intrinsic immunoreactive neurones. Chromaffin cells were immunoreactive for the P2X6 receptor antibody. The widespread and specific distribution of P2X receptor subtypes in the adrenal gland suggests significant roles for purinergic signalling in the physiology of the guinea pig adrenal gland.
Immunohistochemical Assessment of Collagen Types I, III, IV and VI in Biopsy Samples of the Bovine Uterine Wall Collected during the Oestrous Cycle
Authors: Boos Alois
Published: April 2003

Uterine biopsies were collected at cycle days 1 (oestrous), 8, 15 and 19 in six cows. Unfixed cryostat sections were used to immunolocalise collagen types I, III, IV and VI by an indirect FITC method. Collagen I was sparsely found in the endometrium where it formed a fine meshwork of thin fibres directly below the surface epithelium, clearly visible only at cycle days 8 and 15. Collagen III formed the bulk of connective tissue fibres and was arranged in fine aggregates within the superficial endometrial stroma, while in the deeper areas it consisted of many thick fibre bundles. Collagen IV was found in basement membranes underlying all endometrial epithelia. Furthermore, it surrounded smooth muscle cells of blood vessels. A few single fibrils also stained positively within the endometrial stroma, more numerous at cycle days 1 and 19 as compared to days 8 and 15. Collagen VI formed a mesh of fine and pericellularly situated fibrils within the endometrial stroma. The contribution of the collagen types studied to the connective tissue of caruncles, blood vessels, lymph follicles, and myometrium is also reported. The results of the present study indicate that the connective tissue of the bovine uterine wall is composed of different collagen types, which exhibit a characteristic distribution pattern each. The day of cycle may influence amounts and organisation of collagen types I and IV as demonstrated here at the light-microscopical level.
Towards the Molecular Basis of Sperm and Egg Interaction during Mammalian Fertilization
Authors: Wassarman Paul M. , Litscher Eveline S.
Published: April 2003

During the past 2 decades, a number of genes have been cloned from mammals which encode polypeptides that participate in the process of fertilization. Among these are glycoproteins ZP1–3 that constitute the zona pellucida of eggs from mice to human beings. In mice, one of these glycoproteins, mZP3, acts as a primary sperm receptor and acrosome reaction-inducer. The evidence suggests that acrosome-intact sperm recognize and bind to a specific class of mZP3 oligosaccharides present on two serine residues (O-linked) located near the carboxy-terminus of the polypeptide. Mutagenesis of either of these residues results in the synthesis of an inactive form of the receptor. Therefore, mammalian fertilization is a carbohydrate-mediated event. It is possible that changes in the structure of these oligosaccharides (e.g., composition, sequence, linkages, modifications, etc.) could account for species-specific binding of sperm to eggs. Stably transfected somatic cells, null mutant animals, and DNA constructs are now available to test this possibility both in vivo and in vitro.
Sperm Adhesion Molecules: Structure and Function
Authors: Jansen Stephan , Ekhlasi-Hundrieser Mahnaz , Töpfer-Petersen Edda
Published: April 2003

Fertilisation is a unique event in which the morphologically disparate gametes recognise, bind and fuse with each other. This event follows a highly regulated schedule of biochemical interactions, in which molecules are involved that mediate cell adhesion, signal transduction and the initiation of metabolic pathways. A plethora of molecules has been found on the male gamete and with regard to the different protein structures it is almost impossible to overlook the structures involved. Even more, carbohydrate structures cause an additional diversity with regard to the generation of surface structures. In this communication we try to elucidate the structures of proteins that have been known so far. We have focussed on spermadhesins, the zonadhesin, proacrosin and the PH-20 antigen. The variety of structures and also the common features among them as well as the presence of redundant systems are attributable to the evolutionary force of intraspecific sperm competition. This evolutionary force is assumed to be also responsible for the species selectivity observed in these adhesion molecules, which explains the preferential binding of gametes in a homologous system.
New Insights into the Origin, Structure and Role of CD52: A Major Component of the Mammalian Sperm Glycocalyx
Authors: Kirchhoff Christiane , Schröter Sabine
Published: April 2003

The sperm glycocalyx represents the primary interface between the male gamete and its environment, and gamete interaction inevitably involves interaction with this structure. Thus, it has potential significance as a target for antibodies that inhibit sperm function. Still, little is known about the components and biological role of the sperm glycocalyx. Despite the apparent complexity of the sperm membrane, surface carbohydrate labelling experiments show a high selectivity suggesting that carbohydrate side chains of CD52, an unusually short, bipolar glycopeptide of epididymal origin, form major components of the sperm glycocalyx in all mammalian species investigated. Acquisition of the highly sialylated, lipid-anchored CD52 antigen is one of the few well-defined modifications that occur to the sperm membrane during epididymal passage. It would explain changes in lectin-binding patterns and also the remarkable surface charge differences occurring during epididymal transit, most probably attributable to its terminal sialic acid residues. CD52 seems to be immunodominant on human spermatozoa, and antibodies directed against it can agglutinate and completely immobilize human sperm in the presence of complement. Expression of the same peptide backbone in lymphocytes had largely discounted its consideration as a candidate for contraceptive development. However, the recent proof of male-specific modifications indicates the feasibility of this approach.