[Construction and preliminary validation of a risk prediction model for the recurrence of diabetic foot ulcer in diabetic patients].

Objective: To develop a risk prediction model for the recurrence of diabetic foot ulcer (DFU) in diabetic patients and primarily validate its predictive value. Methods: Meta-analysis combined with retrospective cohort study was conducted. The Chinese and English papers on risk factors related to DFU recurrence publicly published in China Biology Medicine disc, China National Knowledge Infrastructure, Wanfang Database, VIP Database, and PubMed, Embase, Cochrane Library, and Web of Science, and the search time was from the establishment date of each database until March 31st, 2022. The papers were screened and evaluated, the data were extracted, a meta-analysis was performed using RevMan 5.4.1 statistical software to screen risk factors for DFU recurrence, and Egger's linear regression was used to assess the publication bias of the study results. Risk factors for DFU recurrence mentioned in ≥3 studies and with statistically significant differences in the meta-analysis were selected as the independent variables to develop a logistic regression model for risk prediction of DFU recurrence. The medical records of 101 patients with DFU who met the inclusion criteria and were admitted to Affiliated Hospital of Guizhou Medical University from January 2019 to June 2022 were collected. There were 69 males and 32 females, aged (63±14) years. The receiver operating characteristic (ROC) curve of the predictive performance of the above constructed predictive model for DFU recurrence was drawn, and the area under the ROC curve, maximum Youden index, and sensitivity and specificity at the point were calculated. Dataset including data of 8 risk factors for DFU recurrence and the DFU recurrence rates of 10 000 cases was simulated using RStudio software and a scatter plot was drawn to determine two probabilities for risk division of DFU recurrence. Using the ß coefficients corresponding to 8 DFU recurrence risk factors ×10 and taking the integer as the score of coefficient weight of each risk factor, the total score was obtained by summing up, and the cutoff scores for risk level division were calculated based on the total score × two probabilities for risk division of DFU recurrence. Results: Finally, 20 papers were included, including 3 case-control studies and 17 cohort studies, with a total of 4 238 cases and DFU recurrence rate of 22.7% to 71.2%. Meta-analysis showed that glycosylated hemoglobin >7.5% and with plantar ulcer, diabetic peripheral neuropathy, diabetic peripheral vascular disease, smoking, osteomyelitis, history of amputation/toe amputation, and multidrug-resistant bacterial infection were risk factors for the recurrence of DFU (with odds ratios of 3.27, 3.66, 4.05, 3.94, 1.98, 7.17, 11.96, 3.61, 95% confidence intervals of 2.79-3.84, 2.06-6.50, 2.50-6.58, 2.65-5.84, 1.65-2.38, 2.29-22.47, 4.60-31.14, 3.13-4.17, respectively, P<0.05). There were no statistically significant differences in publication biases of diabetic peripheral neuropathy, diabetic peripheral vascular disease, glycosylated hemoglobin >7.5%, plantar ulcer, smoking, multidrug-resistant bacterial infection, or osteomyelitis (P>0.05), but there was a statistically significant difference in the publication bias of amputation/toe amputation (t=-30.39, P<0.05). The area under the ROC curve of the predictive model was 0.81 (with 95% confidence interval of 0.71-0.91) and the maximum Youden index was 0.59, at which the sensitivity was 72% and the specificity was 86%. Ultimately, 29.0% and 44.8% were identified respectively as the cutoff for dividing the probability of low risk and medium risk, and medium risk and high risk for DFU recurrence, while the corresponding total scores of low, medium, and high risks of DFU recurrence were <37, 37-57, and 58-118, respectively. Conclusions: Eight risk factors for DFU recurrence are screened through meta-analysis and the risk prediction model for DFU recurrence is developed, which has moderate predictive accuracy and can provide guidance for healthcare workers to take interventions for patient with DFU recurrence risk.

[Analysis of follow-up results of chrono-chemotherapy or conventional chemotherapy combined with intensity modulated radiotherapy in locally advanced nasopharyngeal carcinoma].

Objective: To evaluate the long-term effect and safety of chrono-chemotherapy combined with intensity modulated radiotherapy (IMRT) in locally advanced nasopharyngeal carcinoma (NPC). Methods: 160 patients with locally advanced NPC were randomly divided into a chrono group and conventional group according to random number table. In the first stage, all patients underwent two cycles of induced chemotherapy, consisting of docetaxel, cisplatin and 5-Fu every 21 days. Notably, patients received chrono-moduated chemotherapy according to circadian rhythm in the chrono group, and conventional chemotherapy in the conventional group. Then, 21 days after the completion of first stage, three cycles of concurrent cisplatin chemotherapy every 21 days were given to all patients during IMRT. The median follow-up after the completion of radiotherapy was 31 months. Long-term side effects and the survival of patients were observed. Results: Patients in the chrono group had significantly lower rates of hearing loss (22.72%), dysphagia (0) and neck fibrosis (4.54%) compared with those in the conventional group (39.13%、8.69%, 15.94%, respectively, all P<0.05). Meanwhile, the 1- year overall survival rates (97.0% vs 92.8%), 3-year overall survival rates (80.3% vs 81.2%), 1-year progression free survival rates (95.5% vs 87.0%), 3-year progression free survival rates (71.2% vs 73.9%), 1-year locoregional relapse-free survival rates (97.0% vs 95.7%), 1-year locoregional relapse-free survival rates (92.4% vs 92.8%), 1-year distant metastasis-free survival rates (97.0% vs 98.6%) and 3-year distant metastasis-free survival rates (90.9% vs 91.3%) between the chrono group and the conventional group were not statistically significant (all P>0.05). Conclusions: Compared with conventional chemotherapy, chrono-chemotherapy combined with IMRT didn't affect long-term survival, but reducing the incidence of adverse events in patients with locally advanced NPC.

A randomized phase II trial of induction chemotherapy followed by cisplatin chronotherapy versus constant rate delivery combined with radiotherapy.

Chronotherapy is no longer a novel concept in cancer treatment after approximately 20 years of development. Many clinical trials have provided strong supporting evidence that chronomodulated treatment yields better results than a traditional dosage regimen. This study aimed to evaluate the adverse reactions, effect on immune functions, and therapeutic efficacy of chronomodulated infusion versus flat intermittent infusion of cisplatin (DDP) combined with intensity-modulated radiation therapy (IMRT) in patients with locoregionally advanced nasopharyngeal carcinoma (NPC). A total of 148 patients with biopsy-diagnosed untreated stage III-IVb NPC were randomly assigned to undergo two cycles of chronomodulated infusion (study group) or flat intermittent infusion (control group) of DDP (100 mg/m2 on day 1, 21 days/cycle) synchronized with radical radiotherapy. Patients in the study group received chronomodulated infusion, with peak delivery of DDP at 16:00 pm. Patients in the control group received a routine constant rate of infusion. Both groups were treated with the same radiotherapy techniques. Over a median follow-up of 20 months, the study group had better outcomes for adverse effects and immune functions compared with the control group. During the phase of concurrent chemoradiotherapy, the incidence of nausea, vomiting, and oral mucositis in the study and control groups was 66.7% and 79.5% (p < 0.05), 47.9% and 71.2% (p < 0.05), and 73.9% and 87.7% (p < 0.05), respectively. There was no significant difference in 2-year overall survival, progression-free survival, and distant metastasis-free survival between the two groups (p > 0.05). Chronochemotherapy significantly reduced the incidence of adverse reactions and enhanced the tolerance for treatment without affecting survival. It is worth mentioning that reduced destruction of immune function is a novel area of exploration in chronotherapy research.

Prognostic significance of downregulated BMAL1 and upregulated Ki-67 proteins in nasopharyngeal carcinoma.

This study assessed the prognostic value of BMAL1 and Ki-67 expression in patients with nasopharyngeal carcinoma. Level of BMAL1 mRNA was assessed in tissue specimens from 36 nasopharyngeal carcinomas and 20 nasopharyngeal chronic inflammations using quantitative reverse transcriptase-polymerase chain reaction. Expression of BMAL1 and Ki-67 proteins was analyzed immunohistochemically in 90 paired nasopharyngeal carcinoma and distant normal tissues. The Kaplan-Meier curves and the Log-rank test were used to calculate prognostic significance stratified by BMAL1 and Ki67 protein expression and the COX regression model was to analyze the multivariate prognosis. BMAL1 mRNA was significantly reduced in nasopharyngeal carcinoma (4.67 ± 0.27 versus 6.64 ± 0.51 in chronic inflammation tissues, p = 0.002). Level of BMAL1 mRNA was associated with tumor distant metastasis (3.37 ± 0.66 versus 5.04 ± 0.27 compared with non-metastasis, p = 0.011). Level of BMAL1 protein was also reduced in tumor tissues and BMAL1 expression was associated with better 1-, 3- and 5-year overall survival (OS) of cancer patients (92.6%, 69.2% and 62.3% versus 59.1%, 40.9% and 0% in patients with low BMAL1 expressed tumors; p = 0.000). BMAL1 expression and age were independent prognostic factors for OS (p = 0.032). Furthermore, Ki-67 expression was high in tumor versus normal tissues and associated with poor OS of cancer patients (p = 0.035). The Pearson correlation analysis showed that there was an inverse association between BMAL1 and Ki-67 protein expression (p = 0.021). This study demonstrated that lost BMAL1 and Ki-67 overexpression were associated with poor OS of nasopharyngeal carcinoma patients.

[Impact and changes of maternal hemoglobin on birth weight in pregnant women of Zhuang Nationality, in Guangxi].

Objective: To investigate the hemoglobin (Hb) levels during pregnancy and Hb changes from early pregnancy and association with birth weight on infants. Methods: Mothers of Zhuang Nationality who participated in the pregnancy care program and delivered at the Pingguo County Hospital from May 2013 to May 2015 were included in this study. Retrospective analysis was applied to collect data of health care and pregnancy outcomes. Multiple regression analysis and unconditional logistic regression model were used for data analysis. Results: The mean birth weight appeared as (313 5.92±435.84) grams. The Hb levels at early pregnancy showed significantly positive association with birth weight. Results from our study demonstrated that when Hb levels increased + 1 g/dl at early pregnancy, birth weight would increase 17.61(95% CI: 0.60-34.67) grams, in the adjusted model. The Hb levels at late pregnancy were significantly inversely associated with birth weight. Our findings suggested that when Hb levels increased + 1 g/dl at late pregnancy, birth weight would reduce 19.61(95% CI: -37.53 --1.70) grams in the adjusted model. Changes in Hb from early pregnancy stages were significantly inversely associated with birth weight after adjusting for confounders and Hb levels in the early pregnancy stages. The results also indicated that when Hb levels increased a + 1 g/dl from early to late pregnancy, the birth weight would decrease 32.63 g(95% CI: -48.93--16.32). Compared to the non-anemia group, the anemia group showed significantly increase of small-for-gestational-age (SGA)(OR=1.58, 95%CI: 1.08-2.32) in early pregnancy. Compared to women under the most reduction status, women with the least reduction had a significantly increase of SGA (OR= 1.87, 95% CI:1.24-2.81) among their infants. With the magnitude of reduction on Hb concentration during pregnancy, the risk of delivering babies with SGA showed a gradual trends of increase. Conclusion: Hb levels at early pregnancy were positively associated with birth weight, but the changes of Hb were inversely associated with birth weight at late pregnancy, in women of Zhuang Nationality. Anemia in early pregnancy and the low amplitude of decreased Hb concentration during pregnancy were both risk factors for newborns under less gestational ages.

Biomimetic evolutionary analysis: testing the adaptive value of vertebrate tail stiffness in autonomous swimming robots.

For early vertebrates, a long-standing hypothesis is that vertebrae evolved as a locomotor adaptation, stiffening the body axis and enhancing swimming performance. While supported by biomechanical data, this hypothesis has not been tested using an evolutionary approach. We did so by extending biomimetic evolutionary analysis (BEA), which builds physical simulations of extinct systems, to include use of autonomous robots as proxies of early vertebrates competing in a forage navigation task. Modeled after free-swimming larvae of sea squirts (Chordata, Urochordata), three robotic tadpoles (;Tadros'), each with a propulsive tail bearing a biomimetic notochord of variable spring stiffness, k (N m(-1)), searched for, oriented to, and orbited in two dimensions around a light source. Within each of ten generations, we selected for increased swimming speed, U (m s(-1)) and decreased time to the light source, t (s), average distance from the source, R (m) and wobble maneuvering, W (rad s(-2)). In software simulation, we coded two quantitative trait loci (QTL) that determine k: bending modulus, E (Nm(-2)) and length, L (m). Both QTL were mutated during replication, independently assorted during meiosis and, as haploid gametes, entered into the gene pool in proportion to parental fitness. After random mating created three new diploid genotypes, we fabricated three new offspring tails. In the presence of both selection and chance events (mutation, genetic drift), the phenotypic means of this small population evolved. The classic hypothesis was supported in that k was positively correlated (r(2)=0.40) with navigational prowess, NP, the dimensionless ratio of U to the product of R, t and W. However, the plausible adaptive scenario, even in this simplified system, is more complex, since the remaining variance in NP was correlated with the residuals of R and U taken with respect to k, suggesting that changes in k alone are insufficient to explain the evolution of NP.

Density-Dependent Multiplication and Survival Rates in Heterodera glycines.

Seasonal multiplication and overwinter survival are density-dependent in Heterodera glycines. At low to moderate population densities, the nematode is capable of large population increases on susceptible soybean cultivars and high rates of oversummer or overwinter survival in the absence of a host. To improve estimates of H. glycines multiplication and survival rates, egg densities were monitored for 12 cropping sequences across 10 years. Log-linear regression analysis was used to describe and compare density-dependent relationships. Growing-season change in H. glycines egg densities was density-dependent for all crops (susceptible soybean, resistant soybean, and nonhost), with slope estimates for the density-dependent relationship greater for susceptible soybean compared with a non-host crop. Overwinter population change also was density-dependent, with similar declines in survival rates observed for all crops as population densities increased. Survival was greater following susceptible soybean compared with resistant soybean, with an intermediate rate of survival associated with non-host crops. Survival estimates greater than 100% frequently were obtained at low population densities, despite attempts to account for sampling error. Rates of growing-season multiplication and survival, when standardized for population density, declined with year of the study. Standardized overwinter survival rates were inversely related to average daily minimum temperature and monthly snow cover.

Recognition of facial affect by children and adolescents diagnosed with social phobia.

This study compared the ability of children with social phobia and children with no psychiatric disorder to accurately judge facial affect. Fifteen children and adolescents with social phobia and 14 control children were asked to identify emotions depicted in slides from the Pictures of Facial Affect. In addition, they rated their level of anxiety on a pictorial Likert scale prior to and upon completion of the facial recognition task. The results indicated that children with social phobia had significantly poorer facial affect recognition skills than normal controls and reported greater anxiety upon completion of the recognition task. Multivariate analysis revealed significant differences between groups in the number of errors based on the type of facial affect. Posthoc analysis indicated that deficits were most pronounced for facial representations of happiness, sadness, and disgust. The results are discussed in relation to an integrated model of social skills training that includes facial affect recognition training as a integral component in treatment programs for children and adolescents with social phobia. Directions for future research with larger samples of more ethnically diverse children and adolescents are presented.

Field assessment of plant derivative compounds for managing fungal soybean diseases.

Natural plant-derived compounds are currently being explored as alternatives for pest control in sustainable agriculture. This study explored the use of two compounds, sesamol and carbenoxolone, in the management of the fungal soybean disease charcoal rot (Macrophomina phaseolina). Previous studies have determined that sesamol and carbenoxolone compounds significantly inhibited fungal pathogen growth and plant disease in vitro. In order to assess the field efficacy of these compounds for fungal disease control, 2 years of field testing of these compounds have been conducted in southeast Kansas. Field treatments of the compounds sesamol and carbenoxolone at three concentrations, 0, 500 and 1000 microg/ml, were applied foliarly at four distinct plant developmental stages. Treatments were applied to plots in random triplicate array and the experiment was repeated during the 1998 and 1999 growing seasons. Disease assessments were based on visual disease ratings, plant mortality and soybean yield analysis. Data were recorded weekly for each treatment plot and statistically analysed using analysis of variance. Results indicate that sesamol and carbenoxolone treatments significantly decreased disease symptoms (11-12%) and plant mortality (24-28%) while significantly increasing soybean yields (18-38%). These results support that plant-derived compounds can have a significant impact on soybean disease management and yield under field conditions.

Effects of Maturity and Determinacy in Soybean on Host-Parasite Relationships of Heterodera glycines.

The effects of soybean maturity and determinacy on the host-parasite relationships of Heterodera glycines were investigated in a field microplot study over 2 years. Determinate and indeterminate isolines of the maturity group (MG) III cultivar Williams 82 and the MG V cultivar Essex were grown in microplots artificially infested with a race 3 isolate of H. glycines at three initial population (Pi) densities (0, 300, and 3,000 eggs/100 cm(3) soil). Soybean seed yields, nematode final population (Pf) densities and reproductive index (Pf/Pi), and root colonization by Macrophomina phaseolina, the causal agent of charcoal rot, were monitored in each year. Seed yields were reduced (P

Characterization of ADG1, an Arabidopsis locus encoding for ADPG pyrophosphorylase small subunit, demonstrates that the presence of the small subunit is required for large subunit stability.

Two mutants of Arabidopsis have been isolated that affect ADPG pyrophosphorylase (ADGase) activity. Previously, it has been shown that ADG2 encodes the large subunit of ADGase. This study characterizes the adg1 mutant phenotype and ADG1 gene structure. RNA blot analyses indicate that the adg1-1 mutant accumulates transcripts encoding both the large and small subunits of ADGase, while the adg1-2 mutant accumulates only large subunit transcripts. RFLP analysis and complementation of adg1 mutants with the ADGase small subunit gene demonstrate that ADG1 encodes the small subunit. Sequence analysis indicates that adg1-1 represents a missense mutation within the gene. Western blot analysis confirms that adg1 mutants contain neither the large nor the small subunit proteins, suggesting that the presence of functional small subunits is required for large subunit stability.

A device to prevent jaw clenching.

This article describes a device that is intended to prevent the clenching of the teeth. The principle involved is that to clench the teeth for an extended period, an intraoral vacuum must be formed and maintained. A tube or drinking straw held between the lips extending out of the mouth will prevent a vacuum. The article explains and illustrates how such a device can be made that will exploit this principle. Disadvantages and advantages are discussed.

Locomotor design of dolphin vertebral columns: bending mechanics and morphology of Delphinus delphis.

The primary skeletal structure used by dolphins to generate the dorsoventral bending characteristic of cetacean swimming is the vertebral column. In the vertebral column of the saddleback dolphin Delphinus delphis, we characterize the static and dynamic mechanical properties of the intervertebral joints, describe regional variation and dorsoventral asymmetries in mechanical performance, and investigate how the mechanical properties are correlated with vertebral morphologies. Using a bending machine that applies an external load (N m) to a single intervertebral segment, we measured the resulting angular deformation (rad) of the segment in both dorsal extension and ventral flexion. Intervertebral segments from the thoracic, lumbar and caudal regions of the vertebral column were tested from five individuals. Using quasi-static bending tests, we measured the initial (low-strain) bending stiffness (N m rad-1) as a function of segment position, direction of bending (extension and flexion) and sequential cutting of intervertebral ligaments. We found that initial bending stiffness was significantly greater in the lumbar region than in adjacent thoracic and caudal regions, and all joints were stiffer in extension than is predicted (r2 = 0.554) by the length and width of the intervertebral disc and the length of the cranial vertebral body in the segment. Stiffness in flexion is predicted (r2 = 0.400) by the width of the nucleus pulposus, the length of the caudal vertebral body in the segment and the height of the transverse processes from the ventral surface of the vertebral body. We also performed dynamic bending tests on intervertebral segments from the lumbo-caudal joint and the joint between caudal vertebrae 7 and 8. Dynamic bending stiffness (N m rad-1) increases with increasing bending amplitude and is independent of bending frequency. Damping coefficient (kg m2 rad-2 s-1) decreases with increasing bending amplitude and frequency. Resilience (% energy return) increases from approximately 20% at low bending amplitudes (+/-0.6 degree) to approximately 50% at high bending amplitudes (+/-2.9 degrees). Based on these findings, the dolphin's vertebral column has the mechanical capacity to help control the body's locomotor reconfigurations, to store elastic energy and to dampen oscillations.

Interocclusal splint designed to reduce tenderness in lateral pterygoid and other muscles of mastication.

When a patient has discomfort in the muscles of mastication, a palpation test of the lateral pterygoid muscles is positive, and a stress test is positive, the dental occlusion may be a partial cause. The resin splint described here is designed to permit interocclusal contact exclusively at the center of the arches. This device has been shown to reduce tenderness in the lateral pterygoid and other muscles of mastication quickly, usually in 5 to 10 minutes. The splint and its advantages and disadvantages are described.

Mechanical control of swimming speed: stiffness and axial wave form in undulating fish models

The purpose of this study was to investigate the mechanical control of speed in steady undulatory swimming. The roles of body flexural stiffness, driving frequency and driving amplitude were examined; these variables were chosen because of their importance in vibration theory and their hypothesized functions in undulatory swimming. Using a mold of a pumpkinseed sunfish Lepomis gibbosus, we cast three-dimensional vinyl models of four different flexural stiffnesses. We swam the models in a flow tank and powered them via the input of an oscillating sinusoidal bending couple in the horizontal plane at the posterior margin of the neurocranium. To simulate the hydrodynamic conditions of steady swimming, drag and thrust acting on the model were balanced by adjusting flow speed. Under these conditions, the actuated models generated traveling waves of bending. At steady speeds, the motions of the ventral and lateral surfaces of the model were video-taped and analyzed to yield the following response variables: tail-beat amplitude, propulsive wavelength, wave speed and depth of the trailing edge of the caudal fin. Experimental results showed that changes in body flexural stiffness can control propulsive wavelength, wave speed, Froude efficiency and, in consequence, swimming speed. Driving frequency can control tail-beat amplitude, propulsive wavelength, Froude efficiency, relative rate of working and, in consequence, swimming speed. Although there is no significant correlation between rostral amplitude and swimming speed, rostral amplitude can control swimming speed indirectly by controlling tail-beat amplitude and relative power. Compared with live sunfish using undulatory waves at the same speed, models have a lower Froude efficiency. On the basis of the mechanical control of swimming speed in model sunfish, we predict that, in order to swim at fast speeds, live sunfish increase the flexural stiffness of their bodies by a factor of two relative to their passive body stiffness.

Field Response of Soybean in Maturity Groups III-V to Heterodera glycines in Kansas.

Soybean cultivars from maturity groups III-V were grown in Heterodera glycines-infested locations in northeastern and southeastern Kansas from 1991 through 1994. Yield performance and nematode reproduction were significantly (P <0.01) affected by host response to H. glycines and year, whereas effects of cultivars within host response categories and cultivar x year interactions were generally negligible. In northeastern Kansas, H. glycines-susceptible cultivars from maturity groups III-IV yielded 8% less than resistant cultivars across years, whereas in southeastern Kansas, susceptible cultivars from maturity groups IV-V yielded 38% less than resistant cultivars across years. Analyses of yield components suggested that number of pods per plant accounted for most of the differences in seed yields. Heterodera glycines reproduction rates (final population density/initial population density) averaged 0.7 and 1.3 for resistant cultivars and 8.7 and 15.9 for susceptible cultivars in northeastern and southeastern locations, respectively. Results indicated that the relative performance of resistant and susceptible cultivars can be reliably predicted based on preplant egg densities across most environments in eastern Kansas.

Kinematics of birdsong: functional correlation of cranial movements and acoustic features in sparrows.

The movements of the head and beak of songbirds may play a functional role in vocal production by influencing the acoustic properties of songs. We investigated this possibility by synchronously measuring the acoustic frequency and amplitude and the kinematics (beak gape and head angle) of singing behavior in the white-throated sparrow (Zonotrichia albicollis) and the swamp sparrow (Melospiza georgiana). These birds are closely related emberizine sparrows, but their songs differ radically in frequency and amplitude structure. We found that the acoustic frequencies of notes in a song have a consistent, positive correlation with beak gape in both species. Beak gape increased significantly with increasing frequency during the first two notes in Z. albicollis song, with a mean frequency for note 1 of 3 kHz corresponding to a gape of 0.4 cm (a 15 degrees gape angle) and a mean frequency for note 2 of 4 kHz corresponding to a gape of 0.7 cm (a 30 degrees gape angle). The relationship between gape and frequency for the upswept third note in Z. albicollis also was significant. In M. georgiana, low frequencies of 3 kHz corresponding to beak gapes of 0.2-0.3 cm (a 10-15 degrees break angle), whereas frequencies of 7-8 kHz were associated with flaring of the beak to over 1 cm (a beak angle greater than 50 degrees). Beak gape and song amplitude are poorly correlated in both species. We conclude that cranial kinematics, particularly beak movements, influence the resonance properties of the vocal tract by varying its physical dimensions and thus play an active role in the production of birdsong.

New diagnostic and therapeutic mechanical device.

A new device is described that may be used (1) diagnostically to determine the relationship of the occlusion to tenderness in the lateral pterygoid and other muscles of mastication; (2) to relieve ischemic muscle tenderness; (3) to assist in the reduction of articular clicks; and (4) as a positioning device for the registration of physiologic interocclusal relations. The rationale for the causal relationship between the occlusion and lateral pterygoid muscle tenderness is explained.

Occlusal adjustment as treatment for tenderness in the muscles of mastication in category 1 patients.

When a lateral pterygoid muscle is more tender to palpation than the other muscles of mastication, and a stress test is positive, an occlusal cause should be suspected. Patients with lateral pterygoid tenderness are divided into three categories according to two criteria: the position of the condyles in their glenoid fossae and the degree of dysfunction in the articulation. Only patients in category 1, those with a centered condylar position and without dysfunction, are discussed in this article. Occlusal adjustment is executed on the basis of information gathered from radiographs of the temporomandibular joint, diagnostic casts, and leaf gauge measurements of unequal bilateral occlusal contact. The amount of tooth structure requiring removal can be determined by using leaf gauges of differing thicknesses. Occlusal adjustments are performed without mandibular manipulation until the tenderness of the lateral pterygoid muscle is relieved.

Diagnostic tests used in determining the role of the occlusion in temporomandibular joint disorders.

Two diagnostic tests, positive tenderness to palpation of the inferior bellies of the lateral pterygoid muscles and a positive stress test, are helpful in determining whether the dental occlusion is a principal etiologic factor in ischemic pain in the muscles of mastication. To avoid a noxious occlusal contact, the muscles of mastication, and particularly the lateral pterygoid muscles, must increase their activity. The ability of the patient to supply the oxygen for this activity is variable. When it is inadequate, to relieve ischemic pain the muscular activity must be decreased or the oxygen supply increased. The dentist has the option of using four modalities for the treatment of these painful muscles: physiotherapy, drug therapy, psychotherapy, and occlusal therapy. When the lateral pterygoid muscles are not tender to palpation and the stress test is negative, occlusal therapy is not indicated.