bluuebunny/crossref_metadata_2025 huggingface dataset:
A clinical investigation of the morphological changes in the posterior mandible when implant‐retained overdentures are used
Authors: Blum Igor R. , McCord J. Fraser
Published: November 2004

Objectives: The widespread use and broad acceptance of osseointegrated dental implants as a means of retaining and supporting mandibular overdentures provide potentially stable three‐dimensional reference structures, which have been used to examine the morphological changes of the surface contours of the mandibular ridges distal to implants. Unlike traditional methods that tended to measure changes in ridge morphology and quantity radiographically, this prospective study investigated the changes in the sagittal surface contours of the posterior residual ridges over a 1‐year period by an alternative, non‐radiographic method using serial casts of residual ridges of a group of patients.

Material and methods: The residual ridges of the serial casts produced were examined using a profiling apparatus and computer software programs that allowed the orientation, digitised recording and measurement of the sagittal surface contours of the posterior residual ridges of mandibular casts in terms of area (cm2).

Results: Statistical analysis revealed that the detected reductive changes in the surface contour of the posterior residual ridges following the wearing of an implant‐retained mandibular overdenture over a 1‐year period were highly significant (P<0.001).

Conclusion: It is concluded that the methodology presented in this study can be used reliably as an alternative to radiographical examination for detecting changes that occur in the distal residual alveolar ridges of the implant containing edentulous mandible when implant‐retained overdentures are used. Thus, the method presented may be used to contribute to a reduced exposure to ionising radiation for patients wearing implant‐retained overdentures.
A systematic review of the survival and complication rates of fixed partial dentures (FPDs) after an observation period of at least 5 years
Authors: Lang Niklaus P. , Pjetursson Bjarni E. , Tan Ken , Brägger Urs , Egger Matthias , Zwahlen Marcel
Published: November 2004

Objectives: The objective of this systematic review was to assess the 5‐ and 10‐year survival of combined tooth–implant‐supported fixed partial dentures (FPDs) and the incidence of biological and technical complications.

Methods: An electronic MEDLINE search supplemented by manual searching was conducted to identify prospective and retrospective cohort studies on FPDs with a mean follow‐up time of at least 5 years. Patients had to have been examined clinically at the follow‐up visit. Assessment of the identified studies and data abstraction was performed independently by two reviewers. Failure and complication rates were analyzed using random‐effects Poisson regression models to obtain summary estimates of 5‐ and 10‐year survival proportions.

Results: From a total of 3844 titles and 560 abstracts, 176 articles were selected for full‐text analysis, and 13 studies met the inclusion criteria. Meta‐analysis of these studies indicated an estimated survival of implants in combined tooth–implant‐supported FPDs of 90.1% (95 percent confidence interval (95% CI): 82.4–94.5%) after 5 and 82.1% (95% CI: 55.8–93.6%) after 10 years. The survival rate of FPDs was 94.1% (95% CI: 90.2–96.5%) after 5 and 77.8% (95% CI: 66.4–85.7%) after 10 years of function. There was no significant difference in survival of tooth and implant abutments in combined tooth–implant FPDs. After an observation period of 5 years, 3.2% (95% CI: 1.5–7.2%) of the abutment teeth and 3.4% (95% CI: 2.2–5.3%) of the functionally loaded implants were lost. After 10 years, the corresponding proportions were 10.6% (95% CI: 3.5–23.1%) for the abutment teeth and 15.6% (95% CI: 6.5–29.5%) for the implants. After a 5 year observation period, intrusion was detected in 5.2% (95% CI: 2–13.3%) of the abutment teeth. Intrusion of abutment teeth were almost exclusively detected among non‐rigid connections.

Conclusion: Survival rates of both implants and reconstructions in combined tooth–implant‐supported FPDs were lower than those reported for solely implant‐supported FPDs (Pjetursson et al. 2004). Hence, planning of prosthetic rehabilitation may preferentially include solely implant‐supported FPDs. However, anatomical aspects, patient centered issues and risk assessments of the residual dentition may still justify combined tooth–implant‐supported reconstructions.

It was evident from the present search that tooth–implant‐supported FPDs have not been studied to any great extent and hence, there is a definitive need for more longitudinal studies examining these reconstructions.
Relative effects of pre‐ and post‐eruption water fluoride on caries experience by surface type of permanent first molars
Authors: Singh Kiran A. , Spencer A. John
Published: November 2004

Abstract – Objectives:  To determine the relative pre‐ and post‐eruption exposure effects of fluoridated water on the caries experience of different surface types of first permanent molars.

Methods:  Parental questionnaires covering residential history of participants were linked to the oral examinations of 6–15‐year‐old Australian children conducted in 1992 by the School Dental Services of South Australia and Queensland. Percentage of lifetime exposed to optimally fluoridated water pre‐ (PRE) and post‐eruption (POST) was calculated with respect to tooth eruption age. Combined pre‐ and post‐eruption categories were created to test PRE against POST exposure: PRE and POST = 0, PRE < POST, PRE = POST and in the range 0–90% of lifetime exposure, PRE > POST and, PRE and POST ≥ 90% lifetime exposure. These categories were used as indicator variables in linear regression models with PRE and POST = 0 as reference in an analysis of first permanent molar DMFS scores overall and by surface type.

Results:  Participation rates were 69.7% in South Australia (n = 9690) and 55.6% in Queensland (n = 10 195). Compared with the reference, the categories PRE > POST (β = −0.033), PRE = POST (β = −0.028) in the range 0–90% and, PRE and POST ≥ 90% (β = −0.055) showed significantly lower caries overall (P < 0.01), with a similar pattern for pit and fissure surface caries (β = −0.035, −0.031 and −0.052, respectively). Only a high PRE and POST exposure decreased caries levels significantly in the approximal (β = −0.038; P < 0.01) and free smooth surfaces (β = −0.023; P = 0.03).

Conclusions:  Pre‐eruption exposure was important for a caries preventive effect on first permanent molars in children 6–15 years old since post‐eruption exposure alone could not lower caries levels significantly. For pit and fissure surfaces, a high pre‐eruption exposure could decrease caries levels significantly. However, for other surface types, only a high pre‐ and post‐eruption exposure produced a caries preventive effect.
Trophic structure of fish assemblages from Mamoré River floodplain lakes (Bolivia)
Authors: Pouilly M. , Yunoki T. , Rosales C. , Torres L.
Published: November 2004

Abstract –  The fish assemblage of the floodplain of the Mamoré River (Bolivia) was estimated in eight lakes, corresponding to four habitat types, situated on an environmental gradient related to the river distance: lakes situated near the river, in the forested floodplain, at the floodplain edge and lakes isolated in the savanna. This paper documents the diet of 71 fish species (among the 140 recorded) and compares the taxonomic and trophic structure of fish assemblages between four lake types. The diet analysis was conducted to determine five trophic guilds: algivores/iliophages, herbivores, zooplanktivores, invertivores and piscivores. The taxonomic and trophic structures of the fish assemblages were not similar in the different lake types of the Mamoré River. The trophic structure of assemblages showed a coarse pattern of dominance of algivores/iliophages and invertivores, but different situations were observed in relative abundance of the trophic groups in relation to the spatial position of the lakes (except for piscivores). Lakes close to the river appeared more favourable to the microphages (algivores/iliophages, zooplanktivores) although remote lakes appeared more favourable to the macrophages (invertivores, herbivores). These results support the general idea that fish distribution follows a pattern linked to the ecology of the species, and related to environmental characteristics of the lakes.
Diet overlap and consumption patterns suggest seasonal flux in the likelihood for exploitative competition among piscivorous fishes
Authors: Raborn S.W. , Miranda L.E. , Driscoll M.T.
Published: November 2004

Abstract –  Competition, both intraspecific and interspecific, among piscivorous fishes (predators) may be more pronounced in reservoirs because of the artificial nature of these systems and the continuous anthropogenic influences that may not allow natural processes to regulate their densities. Most studies attempting to measure the extent of competition are based on predator–prey balance indices that are annual snapshots and do not account for seasonal changes. We sought to identify times during the year when intra‐ and interspecific exploitative competition for prey was most likely among dominant predators in a large reservoir of the south‐eastern United States. The possibility of interspecific competition was measured by examining the seasonal extent of diet overlap based on samples of stomach contents. The likelihood or severity of this competition was indexed by how well predators met their energy needs. We found predators were realising less of their energy requirements during spring and autumn, and diet analyses showed predators overlapped substantially in their use of prey during those seasons. Thus, exploitative competition was most likely or severe during spring and autumn; furthermore, this competition had the potential to be interspecific as evidenced by resource overlap.
Quantifying the effectiveness of regional habitat quality index models for predicting densities of juvenile Atlantic salmon (Salmo salar L.)
Authors: Hedger R. D. , Dodson J. J. , Bergeron N. E. , Caron F.
Published: November 2004

Abstract –  The suitability of using regional Habitat Quality Index (HQI) models for predicting distributions of juvenile salmon (Salmo salar L.) was examined using data acquired from selected rivers within Québec, Canada. Regional HQI models were derived by identifying preferences of salmon fry and parr for the habitat properties of flow velocity, water column depth and granulometric index (an index of substrate size) for groups of rivers. These were compared with local HQI models, derived from preferences for habitat properties within individual rivers. Relationships between HQI values and densities of juvenile salmon were established through the use of nonlinear regression. In all cases, the regional HQI models were less effective for explaining distributions of juvenile salmon than local HQI models based on individual rivers. Regional HQI models were relatively ineffective when the habitat characteristics of the river to which they were applied differed greatly from the characteristics of the other rivers within the region. It is inferred that the relationship between the effectiveness of the regional HQI model and the difference in characteristics between individual rivers and those of the region may be used in an a priori determination of whether a regional HQI may be applied effectively to any given river.
Isolation and Culture of Amelanotic Melanocytes from Human Hair Follicles
Authors: Zhu Wen‐yuan , Zhang Ru‐zhi , Ma Hui‐jun , Wang Da‐guang
Published: November 2004

We report a method to establish amelanotic melanocytes (AMMC) in culture and we investigate the effects of various components in the culture medium. Normal human scalp from cadaver donors was transected 1 mm below the epidermis, and hair follicles in the remaining dermis were isolated by a two‐step enzyme treatment. The individual hair follicles were washed exhaustively and suspensions of hair follicle cells were prepared and cultured in Eagle's minimum essential medium supplemented with 12‐o‐tetradecanoyl‐phorbol‐13‐acetate (TPA), cholera toxin and keratinocyte serum‐free medium (K‐SFM). Geneticin was used to eliminate contaminating fibroblasts. Proliferation of AMMC was observed after addition of TPA and K‐SFM including bovine pituitary extract (BPE) into the culture medium. Cell type was determined by staining with monoclonal antibodies, NKI/beteb and HMB‐45, which recognize premelanosomal and melanosomal antigens, respectively. The AMMC were also examined using transmission electron microscopy. Treatment with geneticin eliminates the majority of fibroblasts and does not impair the growth of keratinocytes or AMMC. After contaminating fibroblasts and keratinocytes were removed, two distinct cell morphologies remained: (1) large, dendritic and deeply pigmented cells, which did not proliferate and which disappeared by the third passage, and (2) small bipolar cells, which initially were unpigmented and proliferated very rapidly. We observed that TPA at various concentrations stimulated the proliferation of the cells, and at high concentrations could induce the formation of multiple dendrites. K‐SFM including BPE accelerated the proliferation of the cells in a dose‐dependent manner. After passage 3, almost all cells expressed premelanosomal and melanosomal antigens, recognized by NKI/beteb and HMB‐45, respectively. Active mitochondria, abundant rough endoplasmic reticulum, Golgi complexes, ribosomes and melannosomes (predominantly in stages I, II or III with some at stage IV in some AMMC) were observed ultrastructurally in the cytoplasm of the cultured cells.
Evening melatonin and bright light administration induce additive phase shifts in dim light melatonin onset
Authors: Wirz‐Justice Anna , Kräuchi Kurt , Cajochen Christian , Danilenko Konstantin V. , Renz Claudia , Weber Jakob M.
Published: November 2004

Abstract:  In healthy young men, administration of a single light pulse (5000 lux for 3 hr) or a single melatonin pill (5 mg) at 20:40 hr under controlled constant routine conditions of <10 lux, yielded a phase delay and a phase advance, respectively, in the circadian marker of dim light melatonin onset 24 hr later. Phase shifts after combining the two interventions were additive. Melatonin suppression is not necessary for a phase shift by light, and melatonin is not a ‘weak’ Zeitgeber relative to bright light when ambient lighting is strictly controlled.
Melatonin protects against piroxicam‐induced gastric ulceration
Authors: Bandyopadhyay Debashis , Ghosh Goutam , Bandyopadhyay Arun , Reiter Russel J.
Published: November 2004

Abstract:  The antiulcer effect of melatonin on gastric lesions caused by piroxicam was studied with the intent of determining the mechanism of action of this agent. Melatonin dose‐dependently lowered piroxicam and indomethacin‐induced gastric damage with more than 90% inhibition at a dose of 60 mg/kg BW. Increased lipid peroxidation, augmented protein oxidation and decreased glutathione content of the gastric tissue following piroxicam treatment indicated a possible involvement of oxidative stress in this nonsteroidal anti‐inflammatory drug (NSAID)‐induced gastropathy. Pretreatment of rats with melatonin prevented these changes. Oral administration of piroxicam to rats caused a threefold increase in the tissue levels of hydroxyl radical generation, a change significantly attenuated by melatonin. Furthermore, a decrease in the activity of gastric peroxidase and an increase in the activity of gastric superoxide dismutase(s) (SOD) because of piroxicam treatment was attenuated by melatonin pretreatment indicating that the indole possibly exerts its gastroprotective effects through its direct as well as indirect antioxidant activities. The results of the present studies also reveal that melatonin may influence the expression of Cu‐Zn SOD, catalase, cyclooxygenase as well as alpha‐actinin whose levels were found to be altered, following piroxicam treatment. The current studies, therefore, document melatonin's gastroprotective ability against piroxicam‐induced gastric damage and the findings raise the possibility of melatonin being considered as a co‐therapy with piroxicam or other NSAIDs in reducing the gastropathy when long‐term use of these nonsteroidal agents are unavoidable.
MT‐1 melatonin receptor expression increases the antiproliferative effect of melatonin on S‐91 murine melanoma cells
Authors: Kadekaro Ana Luisa , Andrade Luciana N. S. , Floeter‐Winter Lucile M. , Rollag Mark D. , Virador Victoria , Vieira Wilfred , Castrucci Ana Maria de L.
Published: November 2004

Abstract:  Melatonin, a derivative of tryptophan that is present in all vertebrates, was first described in bovine pineal gland. It is known that melatonin is a highly conserved molecule, present also in unicellular organisms and plants. Several effects of melatonin have been described, including receptor‐ and non‐receptor‐mediated actions. Herein, we studied the effects of melatonin on in vitro and in vivo cell proliferation of Cloudman S‐91 murine melanoma cells. We demonstrated that melatonin treatment significantly inhibits S‐91 melanoma cell proliferation in vitro (EC50 = 10−7 m) as well as reduces tumor growth in vivo. We also demonstrated that melatonin directly increases the activity of the antioxidant enzymes catalase and glutathione peroxidase. These effects are most likely triggered through the direct intracellular action of melatonin, since the presence of receptors could not be demonstrated in this cell line. Expression of MT‐1 melatonin receptor by stable transfection, mediated a dramatic antiproliferative melatonin effect (EC50 = 10−10 m) in S‐91 cells. The expressed receptor is negatively coupled to the adenylyl cyclase/cyclic AMP signaling pathway via Gi protein. These results suggest that expression of the MT‐1 melatonin receptor in melanoma cells is a potential alternative approach to specifically target cells in cancer therapeutic treatment.
Influence of Thyroid Autoimmunity and Maternal Age on the Risk of Miscarriage
Authors: Sieiro Netto Lino , Medina Coeli Claudia , Micmacher Eduardo , Mamede Da Costa Sheila , Nazar Luiz , Galvão Daut , Buescu Alexandru , Vaisman Mario
Published: November 2004

Objectives:  Recently, studies have shown an association between antiperoxidase for the detection of thyroid autoimmunity (TAI) and abortion. Another point to be considered is the association of high risk of abortion and maternal age. The aim of the present study was to evaluate if the association between TAI and miscarriage could also be verified whether a population of unselected pregnant young women who normally present a low risk of miscarriage.

Materials and methods:  We studied 534 pregnant women, by determining their serum thyroid antiperoxidase antibodies (TPO‐Abs), thyrotropin (TSH) and free thyroxine (fT4) levels. Our end point was the pregnancy loss or live birth.

Results:  Age ranged from 12 to 49 years (mean ± S.D.; 23.5 ± 5.9). Of 534 women, 29 (5.4%) were TPO‐Ab positive. TSH levels were significantly higher in TPO‐Ab‐positive women compared with TPO‐Ab negative women (median; 1.9 versus 1.1; P = 0.001). Elevated TSH levels were found in 13.8% (4 of 29) of the TPO‐Ab‐positive women compared with only 2.4% (12 of 505) in the TPO‐Ab‐negative women. There were no significant differences in fT4 levels in relation with autoimmunity and risk of miscarriage. The overall risk of miscarriage was 2.4% (13 of 534). Risk of miscarriage was significantly higher among women older than 35 years (7.7%), TPO‐Ab positive (10.3%) and presenting high levels of TSH (12.5%). These factors remained independently associated with the risk of miscarriage in full multivariate analysis.

Conclusions:  We conclude that TAI is independently associated with is a higher risk of miscarriage in a population of unselected pregnant presenting a low risk of miscarriage.
Antichlamydial and Antisperm Antibodies in Patients with Chlamydial Infections
Authors: Dimitrova Dimitrina , Kalaydjiev Svetoslav , Hristov Lyubomir , Nikolov Krasimir , Boyadjiev Todor , Nakov Lyudmil
Published: November 2004

Problem:  Establishing the correlation between antichlamydial antibodies (AchAbs) and antisperm antibodies (ASA) in patients with chlamydial infections.

Method of study:  ASA were studied in sera from patients (142 with genital, 57 with ocular chlamydial infections) and control group (n = 100) by gelatin and tray agglutination test (TAT), sperm immobilization test (SIT) and ELISA. AchAbs were revealed by ELISA.

Results:  A significantly higher (P < 0.05) ASA incidence was noted in patients with genital infections as compared with controls and patients with ophthalmologic infection (P < 0.0001), but not between patients with ophthalmologic infection and controls (P > 0.05). A significant correlation was established between AchAbs and ASA for TAT (r = 0.8214, P = 0.0341), SIT (r = 0.797, P = 0.032) and ELISA (r = 0.8519, P = 0.0313) in patients with genital infections only.

Conclusions:  The genital Chlamydia infection may play a role in the induction of ASA. This is probably a result of the inflammatory process, but not of cross‐reactivity between sperm and Chlamydia trachomatis antigens.
Possible Pathophysiological Roles of Mitogen‐Activated Protein Kinases (MAPKs) in Endometriosis
Authors: Yoshino Osamu , Osuga Yutaka , Hirota Yasushi , Koga Kaori , Hirata Tetsuya , Harada Miyuki , Morimoto Chieko , Yano Tetsu , Nishii Osamu , Tsutsumi Osamu , Taketani Yuji
Published: November 2004

Problem:  Endometriosis accompanies local inflammatory reactions in the peritoneal cavity. We examined the phosphorylation of mitogen‐activated protein kinases (MAPKs), i.e. extracellular signal‐regulated kinase (ERK), p38 MAPK (p38) and c‐Jun N‐terminal kinase (JNK) in endometriotic stromal cells, and their possible pathophysiological roles in endometriosis in relation to proinflammatory substances.

Method of study:  Endometriotic stromal cells were isolated from endometriomas and were cultured for the experiments. Phosphorylation of MAPKs in endometriotic stromal cells treated with interleukin (IL)‐1β, tumor necrosis factor (TNF)α and H2O2 were examined by Western blot analysis. Effects of PD98059, SB202190 and SP600125 (inhibitors of ERK, p38 and JNK, respectively) on IL‐1β‐induced secretion of IL‐6 and IL‐8, and on IL‐1β‐induced expression of cyclo‐oxygenase‐2 (COX‐2) in endometriotic cells were studied. In addition, eutopic endometrial tissues were collected, and the phosphorylation rate of p38 in eutopic endometrial tissues and endometriotic tissues were determined.

Results:  IL‐1β, TNFα and H2O2 stimulated the phosphorylation of ERK, p38 and JNK, while the total amounts of proteins of the respective MAPKs were virtually the same compared with those in the unstimulated controls. Both SB202190 and SP600125 suppressed IL‐1β‐induced secretion of IL‐6 and IL‐8, and PD98059 suppressed IL‐1β‐induced secretion of IL‐8. Both SB202190 and PD98059 suppressed IL‐1β‐induced expression of COX‐2 in endometriotic cells. The p38 phosphorylation rates in the endometriotic tissues were significantly higher than those in the eutopic endometrial tissues of the same patients.

Conclusions:  Given the current theory that inflammatory changes are involved in the progression of endometriosis, MAPKs could play as pivotal intracellular signal transducers in endometriotic cells, and thus have a pathophysiological role in the disease.
P‐96  Fetal endothelial cells in full‐term placenta, but not in first trimester placenta, express FcγRIIb2 mRNA
Authors: Takuya Mishima , Takeshi Takayama , Gen Ishikawa , Toshiyuki Takeshita , Shigeki Matsubara , Mitsuaki Suzuki , John Robinson , Toshihiro Takizawa
Published: November 2004

In the human placenta, IgG‐transport from maternal to fetal blood starts in the second trimester and continues through the third trimester. There are two cellular barriers for IgG‐transport: the first and second barriers are syncytiotrophoblast and fetal endothelial cells (ECs), respectively. Sorting via FcRn is considered the IgG‐transporter in the first barrier. The mechanism of IgG‐transport in the second barrier is not fully understood. Recently, we reported a novel FcγRIIb‐containing compartment that may serve as an IgG‐transporter in the second barrier (Mol Biol Cell 13 (suppl) 548a, 2002). To further investigate the feasibility of the FcγRIIb‐vesicle involvement in IgG‐transport in placental ECs, we have studied FcR‐expression in the developing human placenta by RT‐PCR and direct sequencing analysis. First trimester and full‐term placentas were used. We proved that the FcγRII expressed in villus ECs in full‐term placenta was the b2 isoform. FcγRIIb2 mRNA expression could not be detected in first trimester placenta, while it was expressed in full‐term placenta. In contrast, FcRn mRNA expression was detectable in first trimester placenta as well as in full‐term placenta. These results seem consistent with our hypothesis that in first trimester placenta IgG is transcytosed via FcRn across the first barrier but IgG cannot be transported in the second barrier that does not express FcγRIIb2 and that the FcγRIIb2‐positive compartment is critical for IgG‐transport in the human placenta.
Oral cancer after using Swedish snus (smokeless tobacco) for 70 years – a case report
Authors: Zatterstrom UK , Svensson M , Sand L , Nordgren H , Hirsch JM
Published: November 2004

Whereas the smoking habit has declined significantly in Sweden in recent decades, there has been a marked increase in the consumption of ‘snus’ (oral moist snuff). The use of this smokeless tobacco, exposing the user locally to carcinogenic nitrosamines, raises the question – will the increasing use of snuff eventually lead to a greater incidence of oral cancer? We report the case of a 90‐year‐old man who developed a localized squamous cell carcinoma in the gingival fold under the upper lip, at the exact place where he had regularly placed loose oral snuff for 70 years. Although this is a reminder of a prevailing cancer risk, the time frame indicates that the risk is slight. This is consistent with recent epidemiological reports regarding the minor risk of snuff‐associated cancer in the Scandinavian countries.
Dentin matrix proteins and soluble factors: intrinsic regulatory signals for healing and resorption of dental and periodontal tissues?
Authors: Silva TA , Rosa AL , Lara VS
Published: November 2004

Dentin contains numerous polypeptides and signaling molecules sequestered in a mineralized matrix. The exposure and release of these molecules occur as a consequence of injury to the pulp and periodontal ligament, which may result from luxation, orthodontic movement or infections of tooth and periodontal structures. When released at these sites, dentin constituents have the potential to act on different surrounding cells, including periodontal cells, osteoblasts, osteoclasts and inflammatory cells, and to affect the course of dental disease. Experimental studies have highlighted the interactions between dentin and cells from tooth and periodontal tissues and reveal dentin to be a cell adhesive, signaling and migratory stimulus for various mesenchymal and inflammatory cells. These results support the hypothesis that dentin molecules might function as regulatory signals for the healing and resorption of dental and periodontal tissues. Data from recent and classical investigations are summarized, many open questions are discussed, and current hypotheses concerning the mechanisms of tooth resorption and periodontal healing are outlined. Many questions regarding the importance of dentin as a source of multifunctional molecules remain unanswered and provide important directions for future studies.
Potential pleiotropic effects of Mpdz on vulnerability to seizures
Authors: Fehr C. , Shirley R. L. , Metten P. , Kosobud A. E. K. , Belknap J. K. , Crabbe J. C. , Buck K. J.
Published: November 2004

We previously mapped quantitative trait loci (QTL) responsible for approximately 26% of the genetic variance in acute alcohol and barbiturate (i.e., pentobarbital) withdrawal convulsion liability to a < 1 cM (1.8 Mb) interval of mouse chromosome 4. To date, Mpdz, which encodes the multiple PSD95/DLG/ZO‐1 (PDZ) domain protein (MPDZ), is the only gene within the interval shown to have allelic variants that differ in coding sequence and/or expression, making it a strong candidate gene for the QTL. Previous work indicates that Mpdz haplotypes in standard mouse strains encode distinct protein variants (MPDZ1‐3), and that MPDZ status is genetically correlated with severity of withdrawal from alcohol and pentobarbital. Here, we report that MPDZ status cosegregates with withdrawal convulsion severity in lines of mice selectively bred for phenotypic differences in severity of acute withdrawal from alcohol [i.e., High Alcohol Withdrawal (HAW) and Low Alcohol Withdrawal (LAW) lines] or pentobarbital [High Pentobarbital Withdrawal (HPW) and Low Pentobarbital Withdrawal (LPW) lines]. These analyses confirm that MPDZ status is associated with severity of alcohol and pentobarbital withdrawal convulsions. Using a panel of standard inbred strains of mice, we assessed the association between MPDZ status with seizures induced by nine chemiconvulsants. Our results show that MPDZ status is genetically correlated with seizure sensitivity to pentylenetetrazol, kainate and other chemiconvulsants. Our results provide evidence that Mpdz may have pleiotropic effects on multiple seizure phenotypes, including seizures associated with withdrawal from two classes of central nervous system (CNS) depressants and sensitivity to specific chemiconvulsants that affect glutaminergic and GABAergic neurotransmission.
A phenotypic and molecular characterization of the fmr1‐tm1Cgr Fragile X mouse
Authors: Yan Q. J. , Asafo‐Adjei P. K. , Arnold H. M. , Brown R. E. , Bauchwitz R. P.
Published: November 2004

Fragile X Syndrome is the most common form of inherited mental retardation. It is also known for having a substantial behavioral morbidity, including autistic features. In humans, Fragile X Syndrome is almost always caused by inactivation of the X‐linked FMR1 gene. A single knockout mouse model, fmr1‐tm1Cgr, exists. In this report we further characterize the cognitive and behavioral phenotype of the fmr1‐tm1Cgr Fragile X mouse through the use of F1 hybrid mice derived from two inbred strains (FVB/NJ and C57BL/6J). Use of F1 hybrids allows focus on the effects of the fmr1‐tm1Cgr allele with reduced influence from recessive alleles present in the parental inbred strains. We find that the cognitive phenotype of fmr1‐tm1Cgr mice, including measures of working memory and learning set formation that are known to be seriously impacted in humans with Fragile X Syndrome, are essentially normal. Further testing of inbred strains supports this conclusion. Thus, any fmr1‐tm1Cgr cognitive deficit is surprisingly mild or absent. There is, however, clear support presented for a robust audiogenic seizure phenotype in all strains tested, as well as increased entries into the center of an open field. Finally, a molecular examination of the fmr1‐tm1Cgr mouse shows that, contrary to common belief, it is not a molecular null. Implications of this finding for interpretation of the phenotype are discussed.
Convergent analysis of cDNA and short oligomer microarrays, mouse null mutants and bioinformatics resources to study complex traits
Authors: Ponomarev I. , Schafer G. L. , Blednov Y. A. , Williams R. W. , Iyer V. R. , Harris R. A.
Published: November 2004

Gene expression data sets have recently been exploited to study genetic factors that modulate complex traits. However, it has been challenging to establish a direct link between variation in patterns of gene expression and variation in higher order traits such as neuropharmacological responses and patterns of behavior. Here we illustrate an approach that combines gene expression data with new bioinformatics resources to discover genes that potentially modulate behavior. We have exploited three complementary genetic models to obtain convergent evidence that differential expression of a subset of genes and molecular pathways influences ethanol‐induced conditioned taste aversion (CTA). As a first step, cDNA microarrays were used to compare gene expression profiles of two null mutant mouse lines with difference in ethanol‐induced aversion. Mice lacking a functional copy of G protein‐gated potassium channel subunit 2 (Girk2) show a decrease in the aversive effects of ethanol, whereas preproenkephalin (Penk) null mutant mice show the opposite response. We hypothesize that these behavioral differences are generated in part by alterations in expression downstream of the null alleles. We then exploited the WebQTL databases to examine the genetic covariance between mRNA expression levels and measurements of ethanol‐induced CTA in BXD recombinant inbred (RI) strains. Finally, we identified a subset of genes and functional groups associated with ethanol‐induced CTA in both null mutant lines and BXD RI strains. Collectively, these approaches highlight the phosphatidylinositol signaling pathway and identify several genes including protein kinase C beta isoform and preproenkephalin in regulation of ethanol‐ induced conditioned taste aversion. Our results point to the increasing potential of the convergent approach and biological databases to investigate genetic mechanisms of complex traits.
Suppression of overt gingival inflammation in tobacco smokers – clinical and mechanistic considerations
Authors: Scott DA , Singer DL
Published: November 2004

Abstract:  Gingivitis is a reversible inflammatory disease of the periodontal tissues. Periodontitis, in addition, involves destruction of the supporting structures of teeth. Diagnoses of gingivitis and periodontitis are predominantly dependent on clinical measurements of key inflammatory indices. Smokers are more susceptible to developing periodontal diseases, yet smoking masks overt signs of inflammation, presenting dental professionals with a clinical conundrum. We review the evidence that tobacco smoke may (i) cause acute periodontal vasoconstriction, (ii) inhibit periodontal angiogenesis in response to inflammatory stimuli, and/or (iii) suppress the production of pro‐inflammatory mediators. It is clear that the mechanisms by which cigarette smoking dampens the periodontal inflammatory response are not yet fully understood. Further research into inflammatory suppression is warranted and should point to improved methods of diagnosis, not only in smokers, but also in non‐smokers.
Dental hygiene in Slovakia
Authors: Luciak‐Donsberger C , Križanová M
Published: November 2004

Abstract  This article reports on the development of the dental hygiene profession in Slovakia from a global perspective. The aim is to inform about current developments and to examine, how access to qualified dental hygiene care might be improved and how professional challenges might be met. For an international study on dental hygiene, secondary source data were obtained from members of the House of Delegates of the International Federation of Dental Hygienists (IFDH) or by fax and e‐mail from experts involved in the national professional and educational organization of dental hygiene in non‐IFDH member countries, such as Slovakia. Responses were followed‐up by interviews, e‐mail correspondence, visits to international universities, and a review of supporting studies and reference literature. Results show that the introduction of dental hygiene in Slovakia in 1992 was inspired by the delivery of preventive care in Switzerland. Initiating local dentists and dental hygienists strive to attain a high educational level, equitable to that of countries in which dental hygiene has an established tradition of high quality care. Low access to qualified dental hygiene care may be a result of insufficient funding for preventive services, social and cultural lack of awareness of the benefits of preventive care, and of limitations inherent in the legal constraints preventing unsupervised dental hygiene practice. These may be a result of gender politics affecting a female‐dominated profession and of a perception that dental hygiene is auxiliary to dental care. International comparison show that of all Eastern European countries, the dental hygiene profession appears most advanced in Slovakia. This is expressed in high evidence‐based academic goals, in extensive work with international consultants from the Netherlands and Switzerland, in annual congresses of high professional quality, and in the establishment of a profession, which has not been introduced in all Western EU countries.
Reduction of gingival recession following orthodontic intrusion in periodontally compromised patients
Authors: Re S. , Cardaropoli D. , Abundo R. , Corrente G.
Published: November 2004

Structured Abstract

Authors – Re S, Cardaropoli D, Abundo R, Corrente G

Objectives – To evaluate the role of orthodontic intrusion and alignment in the reduction of gingival recession (REC) around maxillary incisors of adult periodontal patients.

Design – Prospective clinical study.

Setting and Sample Population – Twenty‐eight consecutively treated adult patients, suffering from severe chronic periodontitis and with one upper central incisor extruded and infrabony defect on its mesial site. All patients were seen in a private practice in Turin, Italy. At baseline, all patients presented with REC on the buccal and mesial aspects of the treated teeth.

Measurements and Results – For each patient probing pocket depth (PPD) and REC were assessed at baseline, at the end of treatment and 1‐year after the end of treatment. REC was also evaluated independently in patients with narrow (NPB) or wide periodontal biotype (WPB). All parameters showed improvement between initial and final measurements statistically, and showed no changes between final and follow‐up measurements. Mean mesial PPD decrease was 4.29 mm, with a residual PPD of 2.50 mm. Mean REC reduction was 0.96 mm on the buccal sites and 1.71 mm on the mesial. No statistical difference was recorded on REC values between groups NPB and WPB.

Conclusion – The presented clinical protocol resulted in improvement of all parameters examined. At the end of orthodontic treatment a predictable reduction of REC was reported, both in patients with thin or wide gingiva.
Jaw muscles in older overdenture patients
Authors: Newton James P. , McManus Frank C. , Menhenick Stephen
Published: November 2004

Objective:  To determine, using computer tomography (CT), whether the retention of a small number of teeth in the older adult used to support overdentures could affect the cross‐sectional area (CSA) and X‐ray density of two jaw closing muscles.

Design:  Cross‐sectional study of a group of older patients subdivided into dentate, edentulous and those wearing overdentures supported by two to five teeth.

Subjects:  The sample consisted of 24 subjects aged 55–68 years.

Outcome measures:  CSA and X‐ray density of two jaw closing muscles, masseter and medial pterygoid were measured and evaluated using CT.

Results:  There were no significant differences between left and right jaw muscles, but the CSA of the masseter muscles were significantly larger than the medial pterygoid muscles. The CSA of the masseter and medial pterygoid muscles was significantly smaller in edentulous subjects compared with dentate subjects but no significant difference was observed between subjects wearing overdentures and those with a natural dentition. No significant differences were observed with the X‐ray density between different muscles or dental states.

Conclusion:  The retention of a small number of teeth in the older adult used to support overdentures appears to sustain the CSA of two jaw closing muscles and therefore could enhance these patients’ masticatory ability compared with those who were edentulous.
Oral health and reduction in respiratory capacity in a cohort of community‐dwelling elderly people: a population‐based 5‐year follow‐up study
Authors: Hämäläinen Piia , Suominen Harri , Keskinen Marja , Meurman Jukka H.
Published: November 2004

Objectives:  Several anaerobic bacteria originating in periodontal pockets have been isolated from infected lungs and pharyngeal microflora. Increased bacterial load in lungs is known to be a risk factor for decline in forced expiratory volume during the first second. The aim was to evaluate both cross‐sectionally and longitudinally the association between oral health status and forced expiratory volume during the first second (FEV1) in older residents of the city of Jyväskylä, Finland.

Design:  Cross‐sectional and prospective cohort study over a 5‐year follow‐up.

Setting:  Research laboratory of the University of Jyväskylä.

Participants:  In 1990 dental status and FEV1 were examined in 203 80‐year‐old people, of whom 88 survivors were retested 5 years later.

Main outcome measures:  Primary: dental status and FEV1. Secondary: existence of pulmonary diseases, height, handgrip strength, smoking, and length of education.

Results:  Participants were regrouped into three categories according to their baseline oral health status. At baseline, men with complete prostheses had the lowest FEV1. Five years later the greatest reduction in FEV1 was seen in subjects with poor periodontal status or complete prostheses (−9.4%) while those with healthy periodontal status showed no reduction in FEV1 values (+1.0%, p = 0.006).

Conclusions:  Periodontal infections and complete prostheses may be reservoirs for pathogens which may be harmful and partly explain the observed reduction in FEV1 during ageing.
Usefulness of new wetness tester for diagnosis of dry mouth in disabled patients
Authors: Kakinoki Yasuaki , Nishihara Tatsuji , Arita Masahiro , Shibuya Koji , Ishikawa Masao
Published: November 2004

Objectives:  The condition of dry mouth is an influential factor in the incidence of caries, periodontal disease, fungal infections, masticatory dysfunctions and denture function. Bedridden elderly and disabled persons often suffer from oral dryness and the aim of this study was to evaluate the usefulness of measuring the amount of moisture in the oral mucosa for clinical diagnosis of dry mouth in this group.

Subjects and methods:  The subjects were 20 elderly bedridden individuals, age range 65–89 years old, living in a nursing home and six healthy laboratory researchers, aged 20–46 years old, used as controls. Tongue dorsum moisture measurements were performed using a newly developed wetness tester (L‐SALIVO®), in which the wet portion was measured after 10 s. Further, clinical diagnosis of dry mouth was carried out using a clinical classification scale of the tongue mucosa (grade range, 0–3).

Results:  It was possible to measure tongue dorsum moisture in all subjects with the wetness tester. The average moisture value was 0.1 ± 0.2 mm in elderly subjects with a dry mouth grade of 2 (n = 8) or 3 (n = 12), while the average moisture value in the control subjects was 3.67 ± 1.75 mm with a dry mouth grade of 0 (n = 4) or 1 (n = 2). Tester values and clinical classification showed a positive co‐relationship (r = 0.31, p < 0.05).

Conclusions:  Our results show that this new tester could be useful for evaluating oral dryness and diagnosing dry mouth.
Agreement between bicarbonate measured on arterial and venous blood gases
Authors: Kelly Anne‐Maree , McAlpine Ross , Kyle Elizabeth
Published: November 2004

Objective:  This study aims to determine the extent of agreement between venous and arterial bicarbonate for a group of emergency department patients with respiratory or metabolic illness requiring blood gas analysis as part of their evaluation.

Methods:  This prospective study of patients who were deemed by their treating doctor to require an arterial blood gas analysis to determine their ventilatory or acid‐base status, compared bicarbonate on an arterial and a venous sample taken as close to simultaneously as possible. Data were analysed using bias (Bland‐Altman) methods. Subgroup analyses were performed for the metabolic, respiratory, chronic obstructive airways disease and acidotic subgroups.

Results:  Two hundred and forty‐six patients were entered into the study; 195 with acute respiratory disease and 51 with suspected metabolic derangement. The values of bicarbonate on arterial and venous samples showed close agreement with an average difference between the samples of 1.20 mmol/L (95% limits of agreement being −2.73 to +5.13 mmol/L). Similar agreement was found for all subgroups.

Conclusion:  Venous bicarbonate estimation shows a high level of agreement with the arterial value, with acceptably narrow 95% limits of agreement. These results suggest that venous bicarbonate estimation may be an acceptable substitute for arterial measurement.
Cross reactivity between venomous, mildly venomous, and non‐venomous snake venoms with the Commonwealth Serum Laboratories Venom Detection Kit
Authors: Jelinek George A , Tweed Charles , Lynch Dania , Celenza Tony , Bush Brian , Michalopoulos Nick
Published: November 2004

Objective:  Studies have noted the relatively common occurrence of positive urine results with the Commonwealth Serum Laboratories Venom Detection Kit (VDK) when testing patients with suspected snakebite who are not envenomed. Possible explanations have been false positive test results or subclinical envenoming. We investigated a third possibility, that there is potential for the venom (or saliva) from mildly venomous and non‐venomous snakes to give a positive reading with the VDK.

Methods:  Venoms/saliva from three non‐venomous and seven mildly venomous snake species were tested in the laboratory with the VDK, along with control venoms from four of the five major snake genera (Brown snake, Tiger snake, Death adder and Black snake).

Results:  Two of the venom/saliva samples, from Gould's hooded snake (Parasuta gouldii), a mildly venomous snake, and the Black‐headed python (Aspidites melanocephalus), a non‐venomous snake, caused a positive test for the tiger snake genus. There was also cross‐reactivity between black snake venoms and the tiger snake well of the VDK.

Conclusions:  This study provides a further possible explanation for ‘false positive’ VDK results, that is venom/saliva presence or absorption from mildly or non‐venomous snakes and cross reactivity with venomous snakes on VDK testing. It has implications for antivenom use should it ever be required for more severe envenoming syndromes from mildly or moderately venomous snakes, and for further research. It reinforces the practice of only using VDK testing in patients who show definite evidence of envenoming.
Mesenchymal Stem Cells: Cell Biology and Potential Use in Therapy
Authors: Kassem Moustapha , Kristiansen Malthe , Abdallah Basem M.
Published: November 2004

Abstract: Mesenchymal stem cells are clonogenic, non‐haematopoietic stem cells present in the bone marrow and are able to differentiate into multiple mesoderm‐type cell lineages e.g. osteoblasts, chondrocytes, endothelial‐cells and also non‐mesoderm‐type lineages e.g. neuronal‐like cells. Several methods are currently available for isolation of the mesenchymal stem cells based on their physical and immunological characteristics. Because of the ease of their isolation and their extensive differentiation potential, mesenchymal stem cells are among the first stem cell types to be introduced in the clinic. Recent studies have demonstrated that the life span of mesenchymal stem cells in vitro can be extended by increasing the levels of telomerase expression in the cells and thus allowing culture of large number of cells needed for therapy. In addition, it has been shown that it is possible to culture the cells in xeno‐free environment without affecting their growth or differentiation potential. Finally, the mesenchymal stem cells seems to be hypoimmunogenic and thus allogenic mesenchymal stem cells transplantation is possible. It is envisaged that mesenchymal stem cells can be used in systemic transplantation for generalized diseases, local implantation for local tissue defects, as a vehicle for genes in gene therapy protocols or to generate transplantable tissues and organs in tissue engineering protocols. The results of these initial trials are very encouraging and several clinical trials are under way to study the efficacy and long‐term safety of therapeutics based on mesenchymal stem cells.