Chewing movements in TMD patients and a control group before and after use of a stabilization splint.

PURPOSE: This study assessed the effect of using an occlusal stabilization splint in the maxilla for 6 weeks on certain parameters of chewing movements in subjects with and without temporomandibular disorder symptoms. MATERIALS AND METHODS: Twelve male and 30 female temporomandibular disorder patients with and without a prior whiplash incidence, and individuals without signs and symptoms of temporomandibular disorders participated. The participants formed three groups matched according to gender and age (n = 3 x 14). A maxillary stabilization splint was used during sleep for 6 weeks. An optoelectronic system (MacReflex, Qualisys) was used to record chewing movements at baseline, before using the splint, and after 6-weeks' use of the splint. Calculated parameters were the duration of the chewing cycles, the spatial displacement, and the mean velocity of the mandible while chewing paraffin wax for 20 seconds. RESULTS: On a group basis, the use of an occlusal stabilization splint for 6 weeks did not change the jaw movement parameters in a predictable pattern as recorded under the conditions of this study. On an intraindividual basis, large variations in changes of chewing parameters over time were observed. CONCLUSION: The use of an occlusal stabilization splint for 6 weeks did not alter the jaw movements when chewing a substance with a soft consistency.

Modulation of multidrug resistance gene expression by dexamethasone in cultured hepatoma cells.

Considerable evidence has accumulated indicating that overexpression of P-glycoproteins encoded by the multidrug-resistance (mdr) genes is responsible for the development of collateral resistance to a number of structurally and functionally dissimilar cytotoxic compounds in animal cells. There are three mdr genes (mdr1, mdr2, and mdr3) in the mouse genome and two (MDR1 and MDR2) in the human genome; however, only two mouse genes (mdr1 and mdr3) and one human gene (MDR1) can confer multidrug resistance upon transfection into otherwise drug-sensitive cells. Using RNase protection assay we report here that the steady-state levels of mdr1 and mdr3 messenger RNA were elevated in mouse hepatoma cells treated with dexamethasone (Dex); whereas no induction of mdr2 gene was found. Western blot analyses using anti-mdr1 and anti-mdr3 antibodies revealed that the encoded proteins appeared to be increased, but at much reduced levels. The induction was time and Dex concentration dependent. Nuclear run-on experiments demonstrated that the induction was at least in part by transcriptional control. The induction apparently required new protein synthesis since no increases in mdr1 and mdr3 transcripts was found when cultured cells were simultaneously treated with Dex and cycloheximide. Neither mdr1 nor mdr3 gene was induced in the Dex-treated nonhepatoma cell lines, LMtk- and NIH3T3. Similarly, MDR1 messenger RNA levels were elevated in the Dex-treated human hepatoma line, HepG2, but not in the nonhepatoma, HeLa. This study demonstrated that the hormonal regulation of mdr gene expression is gene and cell type specific.

Sex differences in signs and symptoms from masticatory and other muscles in 19-year-old individuals.

Pain and tenderness of masticatory muscles are often related to muscle tenderness elsewhere in the body. It has been shown that women are more prone to musculoskeletal disorders than men. We sought to determine whether sex differences of muscular symptoms were established by the age of 19. The subjects comprised 51 boys and girls who received a questionnaire regarding the function of their masticatory system, frequency of headache, and neck, shoulder and low back pain. Their masticatory system was examined, and neck and shoulders were palpated. For all variables in the questionnaire girls reported symptoms more often than the boys. Of the subjects 50% had tender chewing muscles upon palpation. Again the girls had the most. There was good correlation between reports of pain in one area as compared to others. The number of clinically tender neck and shoulder muscles correlated with the number of tender masticatory muscles. It was concluded that girls presented more muscular symptoms than boys.

Structural and functional analyses of the promoter of the murine multidrug resistance gene mdr3/mdr1a reveal a negative element containing the AP-1 binding site.

We have previously shown that the multidrug-resistance/P-glycoprotein gene, mdr3/mdr1a, is activated in mouse hepatocellular carcinomas (HCC). In this study, we show that in a number of HCC-derived cell lines (Hepa1c1c, Hepa1c1c-BprC1, and Hepa1-6) mdr3 is expressed at high levels. To investigate transcriptional regulation of mdr3 in these cells, we have isolated a DNA fragment containing the 5' portion of the mouse mdr3 gene and performed a functional analysis of its promoter. Transient transfection assays using various lengths of the promoter sequence to direct expression of the chloramphenicol acetyltransferase (CAT) reporter gene revealed that the sequence located -94 nucleotides upstream from mouse mdr3 transcription start site functions as a negative element in mouse hepatoma cells. A canonical AP-1 binding sequence TGA-GTCA located at -117 is at least in part responsible for the negative effect from the following observations: (i) Alteration of this AP-1 sequence by site-directed mutagenesis enhanced CAT expression. (ii) Expression of CAT reporter gene was elevated when double-stranded DNA containing the AP-1 sequence, but not mutated sequences, was used as a competitor in cotransfection experiment. (iii) Enhancement of the CAT expression was also seen in cotransfection experiments using recombinant plasmid DNA expressing the c-jun/c-fos proteins, which interact with AP-1 sequences. Interestingly, the proximal region of the hamster pgp1 promoter shares striking sequence similarity with that of the mouse mdr3 gene, including the AP-1 site, but the AP-1 site in the hamster promoter serves as a positive regulator. Although previous studies have demonstrated that positive and negative transcription factors can modulate gene expression through interactions with c-jun/c-fos, this is the first study to show that an AP-1 site functions as a negative cis-element in the regulation of gene expression.

Analysis of the Chinese hamster P-glycoprotein/multidrug resistance gene pgp1 reveals that the AP-1 site is essential for full promoter activity.

Recent studies have revealed that the expression of P-glycoprotein/multidrug resistance genes is crucial for the development of resistance to a number of lipophilic cancer chemotherapeutic agents. To better understand the regulatory mechanisms of pgp gene expression, we isolated and characterized a DNA fragment containing the 5' portion of a Chinese hamster pgp gene. DNA sequence analysis revealed that this gene is pgp1, the hamster homologue of murine mdr3/mdr1a. This gene is expressed at a higher level in intestines than in kidney and liver, consistent with the expression pattern for the murine mdr3/mdr1a gene. The major transcription start site, determined by the S1 nuclease protection, RNase protection, and primer extension methods, lies 67 nucleotides upstream of the murine and human downstream transcription start site. A chimera containing 101 base pairs upstream from this start site and the chloramphenicol acetyltransferase (CAT) gene was able to direct CAT expression in transient transfection experiments. The AP-1 site, located at -48 base pairs, was crucial for the full pgp1 promoter activity, as demonstrated by site-directed mutagenesis of this site, enhancement of the CAT expression by cotransfection with the expression vectors encoding c-Jun/c-Fos genes, but sequestration with those containing retinoic acid receptor genes. The sequestration effect could be partially abolished when c-Jun/c-Fos genes were also included in cotransfection. An AP-1 or AP-1-like site is also present at the same location in both human and mouse mdr homologues. The involvement of AP-1 in the expression of mammalian pgp1-class genes is discussed.

Differences in functional variables, fillings, and tooth wear in two groups of 19-year-old individuals.

Fifty-one individuals (28 girls and 23 boys) who had received orthodontic treatment were compared with 47 subjects (19 girls and 28 boys) without such treatment as to maximal mandibular mobility, chewing muscle tenderness, morphologic occlusion, occlusal/incisal state, and degree of tooth wear. All were 19 years old. There were no statistically significant differences between the groups except for the number of teeth present and maximal mouth opening, which were both smallest in those who had received treatment. The first finding is evident, extraction of premolars being an accepted mode of orthodontic treatment. The reduced mouth opening capacity was related to an increased number of individuals with four or more palpably tender muscle sites in that group of individuals.

Signs and symptoms of craniomandibular disorders in two groups of 19-year-old individuals, one treated orthodontically and the other not.

Fifty-one individuals (28 girls and 23 boys) who had received orthodontic treatment were compared as to signs and symptoms of craniomandibular disorders with 47 individuals (19 girls and 28 boys) without such treatment. All were 19 years old. An average of 5 years had elapsed since the termination of the treatment. The examinations enabled calculations of the anamnestic, the clinical dysfunction, and the occlusal indices of Helkimo. There were no statistically significant differences between the groups except with regard to the anamnestic index. Subjects who had not received orthodontic treatment reported most symptoms, but none were severe. In conclusion, there were no substantial differences as to signs and symptoms of craniomandibular disorders in these two groups of individuals.

The reliability of clinical evaluation of some characteristics in complete prosthetics.

The aim of this investigation was to study intra-assessor reliability and the relationship between individual and simultaneous evaluations when retention and stability of complete prostheses and the condition of the residual ridges were clinically assessed according to defined criteria. Further, inter-assessor reliability and the reliability of simultaneous evaluations were studied by evaluating the condition of the residual ridge on two occasions. Nine patients and three prosthodontists participated. Generally, the reliability levels were low and individual deviations from the simultaneous evaluations were common.

Effects of cyclophosphamide on open, granulating skin wounds in rats.

The effect of cyclophosphamide on the healing of open cutaneous wounds was studied in rats. Following intraperitoneal injections of 25 mg/kg body weight every second day for 9 days, only about 7% of the wounds were completely covered by epithelium after 15 days, whereas in the control animals 60% of the wounds were completely epithelialized. Measurements of wound diameters in circular skin wounds revealed unhealed wound areas in the drug treated animals which were significantly larger than those of the control animals. Cyclophosphamide was found to reduce the occurrence of H3-labelled cells in the granulation tissue when evaluated after 11 days. At 15 days there was no difference in the labelling frequency between treated and control animals, indicating reversal of the drug effect.