bluuebunny/crossref_metadata_2025 huggingface dataset:
The Impact of Consanguinity Worldwide
Authors: Jaber Lutfi , Halpern Gabrielle J. , Shohat Mordechai
Published: April 2003

Consanguineous marriages have been practiced for hundreds of years in many parts of the world. The rate of congenital malformations among the offspring is 2.5 times higher than that among the offspring of unrelated parents, mainly due to the expression of autosomal-recessive disorders, and hospitalization for these reasons causes a major financial burden. An increase in sterility and in the rates of abortion, stillbirths, perinatal losses and neonatal deaths has been reported by some authors but not by others. It is generally accepted that the advantages of consanguinity outweigh the disadvantages; however, strategies for reducing the burden require a unique approach as discussed in this article.
Genetic Services in the New Era: Native American Perspectives
Authors: Dukepoo FrankC.
Published: April 2003

American Indians have arrived at a critical point in their more than 500-year history with the United States Government. With the advent of the new bio-revolution, a number of tribes have voiced vehement opposition to genetic patenting, creation of cell lines, transgenic experimentation and cloning. While many are opposed to the Human Genome Diversity Project, Human Genome Project and diversity research currently being conducted by the Indian Health Service, a few embrace the beneficial aspects of biomedical/biogenetic research. Moreover, an increasing number of Indians see the need for and are seeking genetic counseling and other services. This paper briefly describes some of the issues associated with developing and implementing effective genetic services within Native American communities. Problems of access, perception of services, previous experience with genetics and cultural and other barriers are discussed. Recommendations also are rendered to assist health professionals in the development of services.
Archived Specimens: A Platform for Discussion
Authors: Wertz Dorothy C.
Published: April 2003

To facilitate discussion, this paper describes various types of collections of specimens, their uses in research, types of identifiers, requirements for informed consent, third-party access to samples, recontact, and controversial ethical and social issues. There is need for public opinion research on people’s views of these issues, with particular attention to the views of minority groups.
Assessment of Two ‘Low-Tech’ Genetic Health Care Procedures Performed by Prenatal Care Providers in Washington State: Implications for Future Policy Development Activities
Authors: Fineman Robert M. , Bell Thomas M.
Published: April 2003

Equity in health care demands that patients be treated fairly, impartially and with justice. Health care professionals and others have long been aware of the concept of equity, and the many inequities that exist in our health care cystem. As part of our analysis of postpartum data collected between 1993 and 1996 by the Washington Pregnancy Risk Assessment Monitoring System (PRAMS) from self-administered patient surveys, we explored equity as it pertains to two ‘low-tech’ prenatal genetic health care procedures: (1) whether or not prenatal care providers asked their patients about a family history of birth defects/genetic disorders, and (2) whether or not prenatal care providers talked to their patients about prenatal testing for birth defects/genetic disorders. Overall, about 80% of pregnant women reported that they had been asked about their family history of birth defects/genetic disorders, and about 85% said that their prenatal care provider(s) had talked to them about prenatal testing. Maternal characteristics associated with a lower likelihood of receiving these two low-tech genetic health care procedures appeared to be young maternal age, and low education and income levels, regardless of where women with these attributes received their prenatal care (e.g. community, migrant, health department or military health care clinics, private physicians, or health maintenance organizations).
Birth Defect and Risk Factor Surveillance in the Northern and Southwestern Netherlands
Authors: Reefhuis J. , Zandwijken G.R.J. , de Walle H.E.K. , Cornel M.C.
Published: April 2003

Objective: To survey the associations between several risk factors and birth defects, in order to detect potential new teratogens. Methods: Data of the two Dutch European Registration of Congenital Anomalies (EUROCAT) registries collected before January 1, 1998 were used to perform χ2 tests for a large number of risk factors and birth defects. Defects caused by chromosomal or monogenic disorders were analyzed separately. Results: Cross-tabulations of 80 groups of birth defects with 303 risk factors were studied. Of these, 126 combinations had a p value under 0.05, and 34 had a p value under 0.001. Of these 34 associations, some are known in the literature, some were found before in the same databases and some were new associations. Conclusions: This is a good method for generating new hypotheses for associations between risk factors and birth defects. It can be a start for new, more in-depth studies of potential teratogens.
Laser Fluorescence Detection of Demineralization in Artificial Occlusal Fissures
Authors: Ferreira Zandoná A.G. , Analoui M. , Schemehorn B.R. , Eckert G.J. , Stookey G.K.
Published: April 2003

Laser fluorescence (LF) has been used previously to detect early smooth-surface lesions. Although its use for detection of occlusal demineralization has been implicated, it has not been demonstrated. The aim of this study was to determine whether LF could detect demineralization in the base of artificial fissures. To employ LF for detection of occlusal demineralization an apparatus was devised to direct laser light into fissures and simultaneously detect fluorescence from the base of the fissures. Three groups (n = 40/group) of differing fissure types were prepared (straight wall, converging and diverging wall) with either a sound or lesioned base. One half of each group was examined with LF and dye-enhanced LF (DELF); the other half was examined with LF, exposed to plaque, examined with LF and DELF, air-polished and examined with DELF. All images were scored twice as either (1) carious; (2) sound, or (3) undetermined, by a group of 3 examiners. For fissures without plaque, the average sensitivity was higher for DELF (0.76) than for LF (0.54) (p < 0.05). Likewise, the average specificity was higher for DELF (0.64) than for LF (0.29) (p < 0.05). In the presence of plaque, sensitivity was higher for DELF (0.91) compared to LF (0.43); however, specificity was lower for DELF (0.05) compared to LF (0.55). When the fissures were air-polished and then examined with DELF, sensitivity averaged 0.82 (p < 0.05), and specificity increased consistently (average 0.51, p < 0.05). It was concluded that, in the absence of plaque, DELF was a better diagnostic tool than LF for detection of demineralization in artificial fissures.
Electrical Methods in Occlusal Caries Diagnosis: An in vitro Comparison with Visual Inspection and Bite–Wing Radiography
Authors: Huysmans M.-Ch. D.N.J.M. , Longbottom Ch. , Pitts N.B.
Published: April 2003

The aim of this study was to compare in vitro diagnostic performance of three electrical methods for occlusal caries diagnosis with that of visual inspection and bite–wing radiography. One hundred and seven extracted molar and premolar teeth were subjected to the diagnostic methods by 2 operators and subsequently sectioned for histological validation. Electrical measurements were made at site level and at surface level using two different instruments. The diagnostic parameters calculated from the results were: sensitivity, specificity, diagnostic accuracy at a theoretical caries prevalence of 10% and area under the ROC curve. The electrical methods and bite–wing radiography showed higher sensitivity and lower specificity than visual inspection. Diagnostic accuracy was significantly lower for bite–wing radiography and one electrical method than for visual inspection. Overall diagnostic performance of two electrical methods was superior.
A New Microwave Acid Digestion Bomb Method for the Determination of Total Fluorine
Authors: Grobler S.R. , Louw A.J.
Published: April 2003

A new microwave acid digestion method for total fluorine analysis was compared to the reliable reverse-extraction technique. The commercially available Parr bombs which are compatible with microwave heating were modified for this purpose. The Mann-Whitney statistical test did not show any significant differences (p > 0.05) in the determinations of total fluorine in various samples between the two above-mentioned methods. The microwave method also gave high fluorine recoveries (> 97%) when fluoride was added to different samples. The great advantage of the microwave acid digestion bomb method is that the digestion under pressure is so aggressive that only a few minutes is needed for complete digestion (also of covalently bonded fluorine), which reduces the time for fluorine analysis dramatically, while no loss of fluorine or contamination from extraneous sources could take place during the ashing procedure. The digestion solution was made up of 300 μl of concentrated nitric acid plus 537 μl of water. After digestion 675 μl of ∼ 8.5 M sodium hydroxide plus 643 μl of citrate/TISAB buffer was added resulting in an alkaline solution (pH ∼ 12) which was finally adjusted to a pH of ∼ 5.3 for fluoride determination.
Fluoride–Dependent Formation of Mineralized Layers in Bovine Dentin during Demineralization in vitro
Authors: Damen J.J.M. , Buijs M.J. , ten Cate J.M.
Published: April 2003

Demineralization of dentin in the presence of fluoride produces lesions with a mineralized surface layer which becomes thicker and more mineralized with higher fluoride concentrations whereas the lesion depth is hardly affected. The aim of this study was to investigate the effects of the time of fluoride treatment and the amount of fluoride taken up on the properties of the mineralized layer. Discs of bovine dentin embedded in methylmethacrylate with one surface exposed were demineralized in 50 mM acetic acid, 2.2 mM CaCl2, 2.2 mM KH2PO4, pH 5.0. At the start and/or later during the demineralization period, the specimens were incubated individually for 1 or 2 days in 10 ml of the same demineralization solution supplemented with 0.5, 2.0 or 5.0 ppm fluoride, which was then assessed for changes in calcium and fluoride concentrations. After 2, 5 and 8 days, specimens were sectioned for microradiographic analysis so as to follow development of the lesions and the mineralized layers. The results were the following: While demineralization with fluoride present at the first day led to the formation of a surface layer, fluoride present only at a later day produced a subsurface layer, not at the lesion front but closer to the surface. This layer resulted from (re)precipitation and not from preservation of the original mineral. The 'integrated mineral content' of the surface layer increased linearly with the uptake of fluoride, which resulted in an apparent fluorapatite content of about 20 vol%. The profiles of the surface layers remained unchanged during continued demineralization in the absence of fluoride. It was concluded that in the presence of fluoride mineral loss is reduced as a result of the reprecipitation of dissolved mineral ions as a layer of fluoride–enriched apatite. This layer does not offer protection of underlying dentin against continued demineralization.
Developments in Caries Diagnosis and Their Relationship to Treatment Decisions and Quality of Care
Authors: Verdonschot E.H. , Angmar-Månsson B. , ten Bosch J.J. , Deery C.H. , Huysmans M.C.D.N.J.M. , Pitts N.B. , Waller E.
Published: April 2003

This symposium report evaluates the achievements made in caries diagnostic research since the previous symposium held in 1992. The symposium aimed at presenting the state of the art of caries diagnostic methods, on presenting the links between caries diagnosis and subsequent treatment decisions and their effect on the treatment outcomes, particularly the quality of dental care. The variation among dentists in diagnosing (small) caries lesions and in treatment decision making is considerable. This has been explained by the imperfection of caries decision making tests, but also by making incorrect treatment decisions due to incorrect or partial understanding of diagnostic test parameters. Meta–analyses into the performance of caries diagnostic tests revealed that the available quantitative methods are very promising. It was concluded that these methods had high correlations with lesion depth. They were considered suitable to monitor small changes in lesions. Many obstacsel have been experienced in attempting to transfer the outcomes of diagnostic research into clinical practice and it was concluded that caries diagnosis researchers should co–operate with manufacturers to introducing valid new diagnostic tools to the market. Main research priorities for the coming 10 years are to conduct cost–effectiveness and cost–utility studies of caries diagnostic tools, to continue to review the performances of diagnostic tests, to transfer diagnostic knowledge and experience to the general practitioners particularly by constructing evidence–based clinical guide–lines, to study the relationship between diagnosis and treatment decision, and to assess the effect of diagnostic and treatment decisions on the outcome of care.
In vitro Remineralization of in vivo and in vitro Formed Enamel Lesions
Authors: Iijima Y. , Takagi O. , Ruben J. , Arends J.
Published: April 2003

Thin sections of natural white spot enamel lesions (WS) and of artificial in vitro lesions (VL) were remineralized simultaneously in vitro. The sections, clamped in a PMMA holder, were microradiographed at baseline and after remineralization in a calcium– and phosphate–containing solution (pH = 7.0; 1 ppm F) after 2 and 4 weeks. All data were analyzed with respect to baseline. The results show that the lesion depth values did not change significantly during 2 and 4 weeks of remineralization. The mineral accumulation (change in ΔZ), however, was substantial and significant in WS and VL. In WS the change in mineral accumulation was roughly proportional to the amount of mineral at baseline. The WS accumulated more than two times the amount of mineral than VL in the same periods of remineralization. After 4 weeks of remineralization the maximum mineral value Vmax in the surface layer of the WS was nearly up to the sound enamel level ≈87 vol%. This study shows that the technique and calculation procedure described make this single section method attractive for longitudinal demineralization–remineralization studies in vitro or in situ. Both WS and VL samples obviously remineralized in vitro similarly with respect to the baseline. Furthermore, this in vitro work indicates that remineralization inhibitors present in saliva, and previously penetrated into the enamel tissue, do not influence remineralization later on.
Pronase Digestion of Carious Dentin
Authors: Beltz R.E. , Herrmann E.C. , Nordbø H.
Published: April 2003

The aim of this study was to investigate the individual capabilities of the proteolytic enzyme preparation Pronase™, the enzyme collagenase and sodium hypochlorite to disintegrate and solubilize carious dentin. Samples of carious dentin, and samples of sound dentin for comparison, were extracted 4 times in succession for 24 h with buffered solutions of Pronase. Separate carious dentin samples were extracted in the same manner with buffered solutions of collagenase or with aqueous sodium hypochlorite. The extracts, the solid residues left over after the extractions and untreated samples of carious and sound dentin were digested with sulfuric acid–H2O2 and then analyzed for nitrogen content by a special adaptation of the Berthelot color reaction. Although Pronase did not attack sound dentin, it solubilized more than 90% of the nitrogen present in carious dentin. Collagenase solubilized approximately 66% of the nitrogen, whereas sodium hypochlorite released only 12–20% of the nitrogen of carious dentin. In clinical dentistry, chemical disintegration of carious dentin may reduce the need for mechanical removal of sound tooth structure.
Microradiographic and Microscopic Studies on in situ Induced Initial Caries in Irradiated and Nonirradiated Dental Enamel
Authors: Kielbassa A.M. , Schendera A. , Schulte-Mönting J.
Published: April 2003

The objective of this study was to evaluate the onset of initial demineralization in irradiated and nonirradiated human enamel. Enamel specimens were prepared from the lingual and buccal surfaces of 48 freshly extracted, caries–free third molars. Either the lingual or the buccal enamel specimen of each tooth was irradiated with 60 Gy. The remaining enamel sample was not irradiated. Two irradiated and two nonirradiated enamel specimens were inserted into both buccal aspects of each 12 intraoral mandibular appliances. The appliances were worn by 12 persons for 6 weeks throughout day and night. One side was brushed daily with a fluoride–free toothpaste. On the other side plaque was allowed to grow. Individual oral hygiene techniques were performed without any fluorides. During meals, the appliance was stored in 10% sucrose solution. The enamel specimens were cut perpendicular to the enamel surface. Subsequently, the slabs were ground to a thickness of 90 μm, and studied by means of TMR and microscopic techniques. Evaluated data did not show any differences between irradiated and nonirradiated enamel lesions (ANOVA). The onset of caries in irradiated enamel can be hampered by regularly performed oral hygiene techniques.
The Fidelity of Mutans Streptococci Transmission and Caries Status Correlate with Breast–Feeding Experience among Chinese Families
Authors: Li Y. , Wang W. , Caufield P.W.
Published: April 2003

Our previous study reported that the fidelity of mutans streptococci (MS) transmission from mother to infant was gender– and race–specific within a Birmingham, Ala., population. We hypothesized that fidelity might be a function of postnatal nurturing practices. The purpose of the present study was to investigate those factors that could be correlated with MS transmission among Chinese children whose nurturing histories were known. Forty–eight families with 2– to 3–year–old children were selected from two kindergartens of Beijing, China. A questionnaire concerning the childhood nursing practice was obtained from the parents. Dental caries status was examined, and bacterial samples were collected for all participants twice at 6–month intervals. An average of six isolates of MS was picked at random from selective medium from each individual at each visit. Chromosomal DNA fingerprints were performed for all MS isolates to determine the genomic similarity within each family and among individuals. The results showed that 66% of the children at 2–3 years of age harbored MS, and 46% were caries–active. Of those children, 70% were breast–fed. Among the children whose chromosomal DNA fingerprint genotypes of MS matched that of their mothers, 88% were breast–fed compared with only 12% who were not breast–fed (p = 0.03). We also found that children who were breast–fed for more than 9 months were likely to harbor strains of MS common to their mothers (p = 0.04) and experience more dental caries (dmft = 4.4) at 3 years of age compared with children who were breast–fed less than 9 months (dmft = 1.4, p = 0.04). The data suggest that breast–feeding, especially prolonged breast–feeding, may correlate with the fidelity of transmission and that prolonged breast–feeding may contribute to a higher caries rate.
Progression of and Risk Factors for Dental Erosion and Wedge–Shaped Defects over a 6–Year Period
Authors: Lussi A. , Schaffner M.
Published: April 2003

It has been shown that dental erosion is not a very rare condition. Careful observation and clinical experience led us to hypothesize a progression of these lesions with time despite dietary counselling and oral hygiene instruction. The purpose of this study was to determine the progression rate and risk factors of dental erosion and wedge–shaped defects over a 6–year period. In the year 1987, 204 randomly selected persons living in Bern from two age groups (26–30 and 46–50 years) were examined for frequency and severity of dental erosion and wedge–shaped defects. In the year 1993, 55 persons could be re–examined by the same dentist using the same indices. Further, detailed case histories of the patients were recorded and the flow rate and buffering capacity of the saliva were determined. The results indicated a distinct progression of erosion on facial and occlusal surfaces and wedge–shaped defects over the 6–year period. The increase in the defects was more marked in the older age group. Surprisingly, nutritional habits did not change despite thorough informative discussion about erosive foodstuff with every patient during the first session. Multiple linear regression analysis revealed consumption of nutritional acids and age as significant risk factors explaining 28% of the variability of the progression of erosions. The significant factors for the progression of wedge–shaped defects were identified to be frequency of tooth brushing and age, explaining 21% of the variability of the progression of wedge–shaped defects. In summary, there was a definite statistically significant progression of non–carious dental hard tissue defects in our sample. This progression was correlated with age (erosion and wedge–shaped defects), consumption of dietary acids (erosion) and frequency of toothbrushing (wedge–shaped defects).
Fluoride Profiles in Dental Plaque in vivo Formed on Fluoride Pre–Treated Human Enamel
Authors: Arai K. , Kato K. , Nakagaki H. , Toyama A. , Nagai N. , Noguchi T. , Kirkham J. , Robinson C. , Thuy Tran T. , Ha Nguyen T.T.
Published: April 2003

Using a novel device capable of generating plaque in vivo on a natural enamel substrate, it has been possible to determine fluoride profiles from the saliva–plaque interface towards the enamel surface. Fluoride profiles in dental plaques tended to fall from the saliva–plaque interface towards the enamel. The device also offered the possibility of examining fluoride distributions after pre–treatment of the enamel with fluoride in vitro. Fluoride profiles were determined in plaque generated in vivo on enamel surfaces, which had been previously treated with a 900–ppm fluoride solution. The results showed the previously reported fall from the plaque surface, but in addition, a further rise towards the enamel surface was seen. The data imply that enamel loaded with fluoride can release some of this fluoride back into the plaque and may act as a fluoride reservoir.
In situ Acid Resistance of in vivo Formed White Spot Lesions
Authors: Iijima Y. , Takagi O.
Published: April 2003

Thin sections of natural enamel lesions, so–called white spots (WS), and areas of sound enamel (SEn) adjacent to the WS were exposed to an intraoral environment for 2 weeks. Thin sections of WS samples, clamped in a PMMA holder, were microradiographed before and after exposure to intraoral conditions. Acid resistance was evaluated by lesion depth and mineral changes during the cariogenic challenge. The results show that there were statistically significant differences in lesion depth, mineral loss and mineral volume percent at the surface before and after the intraoral cariogenic challenge at least at p<0.05, except for a change in mineral volume percent at the surface of WS samples. This exception indicates that no mineral change occurred in the surface layer of WS. The fact of 2.8 and 1.8 times higher ratios of SEn over WS of mean changes in lesion depth and mineral loss data, respectively, seems to indicate a quantitative difference in acid resistance level of WS lesions compared with the areas of SEn. Regarding the site of mineral changes, a distinctive feature of WS samples is that mineral loss occurs at the bottom of lesions. In contrast, areas of SEn produce a typical subsurface type of lesions. From this in situ study, it can be concluded that the surface of WS samples was apparently much more acid–resistant (at least approximately 2 times) than the areas of SEn that received a similar intraoral acid challenge.
Gonadotropin-Releasing Hormone Receptor mRNA Expression in the Ovaries of Neonatal and Adult Rats
Authors: Kogo H. , Fujimoto T. , Park M.K. , Mori T.
Published: April 2003

Recent studies have shown that gonadotropin-releasing hormone (GnRH) can exert various effects on the rat ovary by acting through its specific receptors. To determine the cell types responsive to the action of GnRH under physiological conditions in the ovary, distribution of the GnRH receptor mRNA was studied histologically by in situ hybridization in neonatal and adult rats. Expression of the luteinizing hormone receptor mRNA was also examined to judge the growing state of follicles and the corpora lutea. In neonatal rat ovaries, no significant GnRH receptor mRNA signal was detected until 5 days after birth. The expression was first observed at 10 days in the interstitial cells. At 15 days of age, the receptor mRNA was expressed in the granulosa cells of most preantral and early antral follicles, while no hybridization signal was detected in oocyte and theca cells. In adult cycling rats, GnRH receptor mRNA was detected mainly in the granulosa cells of most follicles and luteal cells. The granulosa cells of atretic follicles showed a very high level of the mRNA expression throughout their degenerating process. A strong hybridization signal was also detected in the mural granulosa cells of mature follicles. Newly formed (developing) corpora lutea exhibited signals with moderate intensity in the luteal cells, and the older ones showed weaker signals. The finding that the initial expression of GnRH receptor mRNA was seen in the interstitial cells of neonatal ovaries implies an unknown function of the ovarian GnRH receptor in ovarian development. The high level expression of GnRH receptor mRNA in atretic and mature follicles supports the putative roles of GnRH in the induction of follicular atresia and ovulation in rat ovaries.
The Pituitary Intermediate Lobe of the Hydrated and Dehydrated Gerbil
Authors: Lebaili N. , Bensalem M. , Stoeckel M.E.
Published: April 2003

The pituitary intermediate lobe was studied by immunocytochemistry on semithin sections and by electron microscopy in gerbils (Gerbillus pyramidum) caught in summer and winter in the natural biotope or experimentally submitted to chronic hydration or dehydration. In the gerbil, the intermediate lobe was formed by a predominating population of tightly packed melanotrophic cells the immunocytochemical and morphological features of which were comparable to those described in other mammals. A few typical corticotrophic cells were scattered in the contact zone with the neural lobe. Folliculostellate cells labelled with antibodies against glial fibrillary acid protein and vimentin were interspersed between the glandular cells; they formed small follicles in the vicinity of which the apical cytoplasm contained conspicuous dense granules. Both glandular cell types were innervated by axons most probably colocalizing dopamine and γ-aminobutyric acid. In the pituitaries from the gerbils caught in winter, as from those having free access to hydrated food, the melanotrophic cells exhibited morphological characteristics of high functional activity. In the gerbils caught in summer or receiving exclusively dry food, the secretory activity of the cells was obviously depressed. The corticotrophic cells were unaffected. These observations raise the question of the role of the intermediate lobe in the adaptation to desert life.
Sexual Dimorphism in the Rabbit Masseter Muscle: Myosin Heavy Chain Composition of Neuromuscular Compartments
Authors: English Arthur W. , Eason Jane , Schwartz Gail , Shirley Anne , Carrasco Dario I.
Published: April 2003

The myosin heavy chain (MyHC) isoform composition of six adult (>7 months old) male and female rabbit masseter muscles was studied using seven monoclonal antibodies. In matched serial tissue sections, muscle fibers in 10 different neuromuscular compartments were analyzed. Nearly all fibers were found to express one of five phenotypes. They either contained one of four different slow/beta MyHC phenotypes (I1–I4), nearly all of which co-express cardiac alpha MyHC, or they contained type IIa MyHC. Very few fibers contained slow/beta or cardiac alpha MyHC only or both the alpha/slow/beta and IIa isoforms. Most, but not all, of the compartments studied contained similar proportions of fibers of the five major phenotypes, at least within sex. For 7 of the 10 compartments studied, significant sex differences in the proportion of I1 and IIa fibers were found. Males contained more IIa fibers and fewer I1 fibers than females. Fibers of the IIa phenotype were significantly larger than fibers of all of the other phenotypes and larger in males than females.
Transcript-Specific mRNA Trafficking Based on the Distribution of Coexpressed Myosin Isoforms
Authors: Shoemaker Scott D. , Ryan Allen F. , Lieber Richard L.
Published: April 2003

mRNAs encoding four myosin heavy chain (MHC) isoforms were localized in rat skeletal muscle fibers by in situ hybridization. The ratio of MHC transcript signal in the fiber core compared to the fiber periphery was quantified using image analysis. Two distinct patterns of subcellular localization were observed. Type 1 (β-cardiac) and type 2A MHC mRNAs were located preferentially in the muscle fiber periphery, while type 2B and type 2X mRNAs were distributed homogeneously across the fiber cross section. Since most normal muscle fibers express only a single MHC isoform, this difference in mRNA distribution could reflect either variation in the localization of the synthetic apparatus across different fiber types or differences in the trafficking of different MHC transcripts. To examine the basis for the observed differential distribution in normal muscles, mRNA distribution was assessed in muscle fibers that coexpressed multiple isoforms of the fast MHCs (i.e. types 2A, 2X and 2B), which occurred either in the combination type 2A/2X or type 2X/2B. The quantitative mRNA distribution seen in muscle fibers expressing a single isoform was not significantly different compared to that observed for mRNAs coexpressed in the same fiber (p > 0.6). Given the size similarity and homology of our riboprobes, these data suggest that their subcellular localization may be determined by relatively small differences in the sequences of the mRNAs, perhaps by differential binding of RNA sequence motifs to cytoskeletal elements.
Structural and Ultrastructural Study of GH, PRL and SMT Cells in Male Goat by Immunocytochemical Methods
Authors: Gómez M.A. , Garcés-Abadías B. , Muñoz A. , Vásquez F. , Serrano J. , Bernabé A.
Published: April 2003

The structural and ultrastructural characteristics of adenohypophyseal growth hormone (GH)-, prolactin (PRL)- and GH-PRL (SMT)-secreting cells were studied using immunocytochemical techniques in two normal and one lactating male goat. SMT cells were found in both types of males, which showed the same characteristics as those reported for the female. PRL and SMT cells were more frequent in the lactating male, which reflects their greater galactopoietic activity. GH cells did not seem to influence this process significantly.
Clonality of Urogenital Organs as Determined by Analysis of Chimeric Mice
Authors: Lipschutz Joshua H. , Fukami Hiroko , Yamamoto Masami , Tatematsu Masae , Sugimura Yoshiki , Kusakabe Moriaki , Cunha Gerald R.
Published: April 2003

Though the first mammalian chimera was reported in 1961, suitable markers for different animal strains which are easily detectable in histological sections of all or most organs have not existed. Chimeric mice were produced having an excellent histological marker, the C3H antigen, which is strain-specific and fulfills all the criteria for an ideal strain-specific histological marker. Using male and female C3H-Balb/c chimeric mice we examined epithelial cells of urogenital organs and their morphological or functional units, such as the glomerulus, to determine whether individual organs and their morphological subunits were monoclonal or polyclonal in origin. We found that the epithelial parenchyma of most male and female urogenital organs (the prostate, seminal vesicle, epididymis, ovaries, vagina, kidney, ureter and bladder) and their morphological subdivisions were derived from cells of both input strains, indicating a polyclonal origin for each organ and/or organ component. A notable exception was the uterus in which all individual uterine glands examined (n = 403) were found to be either entirely Balb/c or entirely C3H, indicating a monoclonal origin. The clonality of urogenital structures is discussed in terms of the morphogenesis of the urogenital system.
Ultrastructural Study of the Relationship between the Morphogenesis of Filiform Papillae and the Keratinization of the Lingual Epithelium in the Mouse
Authors: Iwasaki S. , Okumura Y. , Kumakura M.
Published: April 2003

Tongues were removed from fetuses of mice on the 15th day of gestation (E15), from newborns (P0), and from juveniles on the 7th day (p7) and on the 21st day (P21) after birth for examination by light microscopy and transmission electron microscopy. In the fetuses at E15, no rudiments of filiform papillae were visible on the dorsal surface of the tongue. No evidence of keratinization was recognized throughout the entire dorsal lingual epithelium. At P0, rudiments of filiform papillae were compactly distributed over the dorsal surface, as are the filiform papillae in the adult, but their tips were rounder than those of the filiform papillae in the adult. Cell columns in the epithelium, with different degrees of keratinization of the type observed in the matured adult were indistinct. However, a keratinized layer was clearly visible on the tip of each filiform papilla. In juveniles at P7, the filiform papillae on the anterior part of the tongue were long and slender, and the anterior and posterior cell columns of the filiform papillae were identical to those in the adult. These results indicate that, in mice, the morphogenesis of filiform papillae advances in parallel with keratinization of the lingual epithelium from the stage just before birth to a stage a few weeks after birth.
Can Exogenous Stem Cells Be Used in Transplantation?
Authors: Boheler Kenneth R. , Fiszman Marc Y.
Published: April 2003

Today’s most urgent problem in transplantation is the lack of suitable donor organs and tissues and as the population ages, demands for organs and tissue therapies will only increase. One alternative to organ transplantation is cell therapy whose aim is to replace, repair or enhance the biological function of damaged tissue or diseased organs. One goal of cellular transplantation thus has been to find a renewable source of cells that could be used in humans. Embryonic stem (ES) cells have the potential to proliferate in vitro in an undifferentiated and pluripotent state. Theoretically, ES cells are capable of unlimited proliferation in vitro. ES cells spontaneously differentiate into derivatives of all three primary germ layers: endoderm, ectoderm and mesoderm, hence providing cells in vitro which can theoretically be isolated and used for transplantation. Furthermore, these pluripotent stem cells can potentially be used to produce large numbers of cells that can be genetically modified in vitro. Once available, this source of cells may obviate some of the critical needs for organ transplantation. Murine ES cells have been extensively studied and all available evidence indicates that all aforementioned expectations are indeed fulfilled by ES cells. ES cells as well as embryonic germ cells have recently been isolated and maintained in culture. The recent descriptions of human ES cells portend the eventual use of allogeneic in vitro differentiated cells for human therapy. This goal, however, is fraught with obstacles. Our aim is first to review the recent advances made with murine ES cells and then to point out potentials and difficulties associated with the use of human ES cells for transplantation.
Embryotoxicity Screening Using Embryonic Stem Cells in vitro: Correlation to in vivo Teratogenicity
Authors: Scholz Gabriele , Pohl Ingeborg , Genschow Elke , Klemm Martina , Spielmann Horst
Published: April 2003

Blastocyst-derived pluripotent embryonic stem (ES) cells of the mouse can be induced to differentiate in culture into a variety of cell types, including cardiac muscle cells. The embryonic stem cell test that makes use of the differentiation of ES cells into cardiomyocytes in a standardized in vitro model was developed to offer an alternative method to comprehensive in vivo studies in reproductive toxicology about toxic effects of chemicals. ES cells of the mouse cell line D3 are investigated for their preserved capability to differentiate following drug exposure, and both ES cells and differentiated fibroblast cells of the mouse cell line 3T3 are comparatively analyzed for effects on viability. The following endpoints are used to classify the embryotoxic potential of chemicals into three classes of in vitro embryotoxicity (non-, weakly or strongly embryotoxic). These endpoints are: (1) the inhibition of differentiation of ES cells into cardiomyocytes after 10 days of treatment, and the decrease of viability (cytotoxicity) of (2) 3T3 cells and (3) ES cells after 10 days of treatment, determined by a 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyl tetrazolium bromide (MTT) test. 50% inhibition concentrations for differentiation (ID50) and cytotoxicity (IC50D3 and IC503T3) are calculated from concentration-response curves. Applying linear analysis of discriminance, a biostatistical prediction model (PM) was developed. This procedure identified three variables, the lg(IC50D3), the lg(IC503T3) and the relative distance between IC503T3 and ID50, that improved the separation of the three classes of embryotoxicity compared to the prediction model that was originally proposed after test development. Unlike the orginal PM, the improved PM incorporates as one variable the relative distance between IC503T3 and ID50, instead of the ratio ID50/IC50D3 that was used previously.
Immunocytochemical and Immunoelectron-Microscopic Study of Somatotrophs in ICR and Nonobese Diabetic Mice
Authors: Manabe Yoshie , Nakatomi Kazufumi , Chikaraishi Mayumi , Takeuchi Sakae , Kobayashi Yuta , Takahashi Sumio
Published: April 2003

Somatotrophs (GH cells) were classified immunoelectron microscopically into three types mainly on the basis of the size of secretory granules in the mouse pituitary of ICR strain. Type I cells contained large secretory granules. Type II cells contained both large secretory granules and small secretory granules. Type III cells contained small secretory granules. All three types of GH cells were found from the neonatal ages to adult. The relative proportion of three types did not change with age, and no sex differences in the relative proportion of the cell types were detected. Type I cells predominate in all age groups observed. In 60-day-old male mice percentages of each type were as follows: type I 93.7 ± 0.1%, type II 5.4 ± 0.8%, and type III 0.9.0 ± 0.4% (n = 5), and in 60-day-old female mice type I 95.2 ± 0.1%, type II 2.7 ± 0.5%, and type III 2.1 ± 0.9% (n = 5). The maximum diameters of the large secretory granules increased from 7 to 60 days of age. The small secretory granules similarly increased in size in female mice, but those in male mice did not change. In the diabetic female mice of the nonobese diabetic (NOD) strains, GH cells in diabetic mice became smaller, and the number and size of secretory granules decreased, indicating diminished GH secretion. However, the relative proportion of each subtype of GH cells did not differ irrespective of the occurrence of diabetes.
Distribution of Interglobular Dentine in Human Tooth Roots
Authors: Sato H. , Kagayama M. , Sasano Y. , Mayanagi H.
Published: April 2003

The present study was designed to examine the distribution of interglobular dentine in human tooth roots. The material comprised 17 teeth, of which 3 were premolars extracted for orthodontic reasons from children 10–12 years of age and the other teeth (4 incisors, 3 canines and 7 molars) were extracted for periodontitis from individuals aged 32–63 years. All teeth were free of caries and cervical dentine defects. Ground sections of the teeth cut longitudinally were stained with basic fuchsin and observed by fluorescence and confocal microscopy as well as transmitted light microscopy. Basic fuchsin stained the dentinal tubules, interglobular dentine and the granular layer of Tomes. These structures appeared intense blue to faint violet with transmitted light microscopy, whereas their staining displayed intense fluorescence with fluorescence microscopy. Therefore, the interglobular dentine could be detected more sensitively with fluorescence and confocal microscopy than with transmitted light microscopy. Typical interglobular dentine was present in coronal dentine in most of the teeth. In the radicular dentin, position and size of the interglobular dentine was different among the teeth examined. Most of the teeth had the interglobular dentine in the cervical part of the roots (type A). Two premolars displayed the interglobular dentine in the coronal half of the root (type B). The types A and B contained large interglobular areas. A small amount of interglobular dentine was restricted to the apical half of the roots of two canines and one molar (type C). In contrast to types A and B which were seen at both labial or buccal and lingual sides of roots, the interglobular dentine of type C was seen only at one side, labial or lingual. Some of the tooth roots did not show any interglobular dentine (type D). Most of the incisors, canines and premolar were types A, B, and C, respectively, and the molars were mixed types A, C, and D. These results suggest that the factors affecting dentinogenesis during root formation are unique for each tooth.
Zona Hardening, Zona Drilling and Assisted Hatching: New Achievements in Assisted Reproduction
Authors: De Vos A. , Van Steirteghem A.
Published: April 2003

Prior to fertilization, the zona pellucida surrounding the mammalian oocyte acts as a species-specific sperm barrier and is involved in sperm binding. After fertilization, the zona plays a role in blocking polyspermic fertilization, it protects the integrity of the preimplantation embryo during early embryonic development, and also helps its oviductal transport. Zona hardening occurs naturally after fertilization in order to ensure this threefold function. A combination of lysins produced by the cleaving embryo or the uterus and physical expansion then reduces the zona thickness in preparation for hatching. Zona hardening, although not readily quantifiable, may also be induced by in vitro culture and by in vivo aging. Indeed, prolonged exposure of human oocytes and embryos to artificial culture conditions seems to impair their ability to implant. Implantation rates are also inversely correlated with advanced female age. Recently, failure of the embryonic zona pellucida to rupture following blastocyst expansion has been put forward as a possible contributing factor in implantation failure. In order to help embryos escape from their zonae during blastocyst expansion, different types of assisted hatching have been developed. Zona drilling involves the creation of an opening in the zona with acidified medium, whereas zona slitting is carried out in the same manner as partial zona dissection. In zona thinning, the zona is just made thinner over a certain area without a hole or a slit being created. More recently, laser-assisted hatching has been introduced. In vitro studies with both mouse and human embryos have indicated that an artificial gap in the zona pellucida significantly improves the hatching ability of blastocysts grown in vitro as compared to non-micromanipulated embryos. However, the clinical relevance of assisted hatching within an assisted reproduction program remains controversial and elusive. Very few randomized studies are available. Most reports are of retrospective analyses which report either no differences in implantation and pregnancy rates between assisted hatching and control embryos or better results after assisted hatching. Five randomized controlled studies suggest that assisted hatching – of no benefit to the overall patient population – might be of value in increasing embryo implantation rates only in selected cases. No further evidence exists for an age-related benefit from assisted hatching in patients with advanced maternal age.
In vitro Fusion of Human Inguinal Hernia with Associated Epithelial Transformation
Authors: Hutson J.M. , Albano F.R. , Paxton G. , Sugita Y. , Connor R. , Clarnette T.D. , Gray A.Z. , Watts L.M. , Farmer P.J. , Hasthorpe S.
Published: April 2003

The processus vaginalis (PV) is a peritoneal diverticulum which forms to allow descent of the fetal testis to the scrotum. During human development fusion and obliteration of the PV often fails to occur with the result that inguinal hernias are the most prevalent congenital abnormality requiring surgery in childhood. Androgen is proposed to regulate testicular descent via the genitofemoral nerve which releases the neuropeptide calcitonin gene-related peptide (CGRP). It is possible that subsequent fusion of the PV and tissue remodelling following descent is indirectly controlled by androgen via CGRP action. An organ culture assay was developed to assess fusion of the PV taken from inguinal herniotomy in infants. Fusion was induced in vitro by CGRP but not by CGRP 8–37, CGRP 27–37 or dihydrotestosterone in equimolar concentrations. Fusion was accompanied by transformation of the epithelium, as shown by staining of intermediate filament proteins, cytokeratin and vimentin. Localization studies for CGRP receptors on 25 specimens indicated CGRP acts on mesenchymal fibroblasts but not directly on PV epithelium suggesting an indirect pathway. Hepatocyte growth factor/scatter factor was found to induce fusion of PV and may be involved as an intermediate molecule in the fusion cascade. This study represents the first approach to understanding the humoral control and underlying mechanism by which the PV fuses.
Morphological Characteristics of Neuromuscular Junctions of the Opossum (Didelphis albiventris) Extraocular Muscles: A Scanning-Electron-Microscopic Study
Authors: Matheus S.M.M. , Soares J.C.
Published: April 2003

Three types of neuromuscular junctions were described in the extraocular muscles of the opossum. The present study demonstrates the three-dimensional characteristics of these neuromuscular junctions after HCl connective tissue digestion. Adult opossum of both sexes were used and the neuromuscular junctions of the extraocular muscles were examined after removal of the intramuscular connective tissue and basal layer. This material was examined with a scanning electron microscope. Two types of ‘en plaque’ neuromuscular junction were described: the continuous type revealed elongated and branched primary synaptic grooves separated from each other by sarcolemma protuberances with different sizes, and the discontinuous or punctiform type which presents very shallow and discontinuous grooves when compared with the former. The multiple neuromuscular junctions were observed as two or three junctions associated with the same muscular fiber. The multiple junctions were present in thin fibers (around 11 μm caliber); the en plaque junctions were associated with large diameter fibers (around 21 μm). This study confirms and reveals the detailed morphological characteristics of the three neuromuscular junction types previously described by transmission electron microscope in the extraocular muscles of opossum.