Prevalence of torus palatinus and torus mandibularis in the Split-Dalmatian County, Croatia

Torus palatinus (TP) and torus mandibularis (TM) are non-pathological outgrowths of unclear etiology that develop from the jaw bone. The purpose of the present study was to report on the prevalence, shape and location of TP and TM in the population of the Central Dalmatian region, Croatia. The study comprised of 1679 subjects, 985 females and 694 males, age range from 9 to 99 years who were examined by clinical examination and analysis of the plaster casts. Torus palatinus was found in 42.9% subjects and torus mandibularis in 12.6% of the subjects. Spindle-shaped torus palatinus was the most frequent type (45.6%). The most frequent type of torus mandibularis was bilateral solitary torus mandibularis (35.4%). Furthermore, torus palatinus was found in 40.1% of the total number of females and in 46.8% of the total number of males, indicating a significantly higher prevalence in the male population (p = 0.006). Torus mandibularis was found in 11.3% of the female population and in 14.6% of the male population, again indicating significantly higher prevalence in the male population (p = 0.046). The results of this study show significantly higher prevalence of torus palatinus and torus mandibularis in the male subjects. Furthermore, no differences in the prevalence of either TM or TP regarding age were found.     

Some observations on the dentition of an isolated group in northeast Poland.

Clinical examination of the teeth and the mouth was carried out on a group of 133 "Old Believers," 54 males and 79 females, and a control group of 138 Poles living in the same area of Augostova in northeast Poland, 63 males and 75 females. Studying the frequency of Carabelli's cusp, shovel-shaped incisors, missing teeth, microdonita, supernumerary teeth, and torus palatinus in both groups, it was found that Carabelli's cusp and torus palatinus are more frequent among Poles. Such differences could be attributed to differences in ethnic origin of the two groups.     

Torus palatinus: a segregation analysis

Segregation analysis of 99 sibships in 2 samples from Venezuela and Japan indicates that a torus palatinus is inherited in simple dominant fashion. The gene shows variable expressivity and penetrance close to 85%, without significant heterogeneity between the populations considered. No evidence of sporadic cases has been found.     

The frequency and anatomical features of torus mandibularis in a Black South African population.

Torus mandibularis is a rounded bony protuberance on the lingual surface of the mandible and usually found above the myolohyoid line, medial to the molar roots. This report describes the frequency and morphology of torus and also proffers the likely cause among black South Africans. A total of 284 modern skeletal specimens were obtained from the Raymond Dart Collection of Human Skeletons at the School of Anatomical Sciences, University of the Witwatersrand. The mandibles were classified into dentate and edentulous, while those with torus, especially in dentate mandibles, were reviewed for side location, type and shape. No measurements were made, consistent with the view that these characteristics are non-metrical and should be assessed by means of a standard observatory procedure. Out of 246 dentate mandibles, 60 (24.4%) were found to have torus and only 1 (4.3%) out of the 23 male edentulous mandibles; the difference is statistically significant (P=2.8%). The torus distribution among males and females was 48 (80%) and 12 (20%), respectively, and again statistically significant (P< 0.05). Prevalence of torus was highest in the 40–60 years age group. The morphology of the torus showed that 37 (61.7%) were bilateral in location, 42 (70%) were of the solitary type and 31 (51.7%) were round in shape. The formation of torus follows the threshold model which holds that this is primarily a genetic trait, but with environmental factors such as mechanical stress necessary for its development.     

Mandibular torus morphology

The morphology of the mandibular torus was examined, and comparisons were made between a Medieval Norse skeletal population from Greenland and a 14th to 17th century Greenland Eskimo skeletal series. Three parameters were analyzed: degree of development (on a 4-point scale), position and length, and surface morphology according to the number of knobs, or lobuli. It was found that the Eskimos have a high frequency of weakly developed tori and no cases of the extreme development, while over 20% of the Norsemen had tori in the “extreme” category. The Norse torus was generally found to be longer than that of the Eskimos, and both groups exhibited a slight asymmetry between the sides, the torus on the left side tending to be longer and more forward in position than the right. A great difference was found in surface morphology. The Norse torus is in general very irregular, while the Eskimo torus is rather smooth. These differences are believed to be genetically determined.     

Palatine torus in the pre-conquest inhabitants of the Canary Islands.

An unusually high frequency of palatine torus in prehistoric Canary Islands skeletal remains is investigated in terms of population origins, evolutionary forces (gene flow and genetic drift) and environmental effects. Palatine torus frequencies (percent presence) are compared between the Canary Islands sample and skeletal samples from proposed ancestral regions, including northwest Africa, northeast Africa, sub-Saharan Africa, southern Europe, northern Europe and western Asia. The frequency of palatine torus is much higher in the Canary Islands sample (23.8%) than in samples from Northern and sub-Saharan Africa (1.8-6.1%), southern Europe (7.5%) and western Asia (2.1%), but is much lower than in the sample from northern Europe (57.4%). Because biological and archaeological evidence provide strong support for a northwest African origin for indigenous Canary Islands populations, the relatively high occurrence of palatine torus in the Canary Islands populace cannot be explained by an alternative ancestry; rather, it may be best explained by either evolutionary forces such as genetic drift or gene flow, or by environmental forces, such as hard chewing or a heavy dependence on marine foods. Genetic drift and gene flow seem less likely, since frequencies of other dental traits known to be under strong genetic control do not differ greatly between the prehistoric Canary Islands and northwest African samples. Environmental factors such as diet seem the most likely explanation and may include heavy consumption of marine foods, which has been implicated in torus formation.     

A study of phi X-174 DNA torus and lambda DNA torus tertiary structure and the implications for DNA self-assembly

Hydrated torus shaped complexes were examined by transmission electron microscopy in both spermidine-condensed linear and nicked circular phi X-174 DNA and lambda DNA preparations. Freeze-etch replicas of both these torus samples, produced with very low Pt metal deposition levels (9APt/C), were found to have circumferentially wound single DNA double helix size surface fibers in the range of 30A width. Measurements of torus inner and outer circumference as well as ring thickness were performed. Observed differences in the torus dimension distributions from circular phi X-174 DNA and linear phi X-174 DNA may be related to the different topological constraints on DNA folding in these two samples (1). On the basis of annulus thickness measurements phi X-174 DNA toruses, in contrast to lambda DNA toruses, were observed to fall into two classes identified as being formed from monomer DNA condensation and multimer DNA condensation. All of the torus substructure and population dimensions observed here are consistent with the continuous circumferential DNA winding model of torus organization proposed by Marx and Reynolds (1) to explain the micrococcal nuclease cleavage properties of the toruses. End-on view measurements of the torus thickness were made from micrographs obtained by extensive tilting of the object replica. These direct measurements confirmed quaternary structure interpretations made from simple strand packing models. We compared the measured torus properties in this linear DNA size series (5386-48000 bp). With increasing DNA length the pattern of DNA strand self-assembly was found to be more varied producing lambda DNA toruses of varying shape. The relevance of our study to the problem of lambda bacteriophage DNA head packaging was discussed.     

Analysis of contingency table data on torus mandibularis using a log linear model

The hypothesized sexual difference in the incidence of torus mandibularis in Eskimoid groups, as well as age and group differences, was studied in two Northwest Territories Eskimo groups and in an Aleut group (examined by Moorrees). The data were analyzed using statistical methods new to the field of anthropology. The method analyzes data sampled from a multinomial distribution. A hierarchy of log linear models are fitted to the cell counts of a contingency table. An iterative proportional fitting procedure is used to obtain expected cell counts under each log linear model. The “goodness of fit” of each model is tested by the log likelihood ratio. This statistic can be partitioned into additive components such that differences between models can be tested. In this way a “best” model, from the hierarchy of models, is chosen. Among these three groups of Eskimos, the incidence of torus mandibularis was not affected by sex but was affected by age and was different between the three groups.     

Torus mandibularis among Icelanders

Nine hundred and seventy-six Icelandic schoolchildren (489 ♂ and 487♀) were surveyed for occurrence of torus mandibularis. No sexual dimorphism was observed but there was a statistically significant difference between areas. A highly significant positive association between age and frequency of occurrence and size was also observed. Single tori were more prevalent than multiple ones and also appeared earlier. Symmetrical occurrence predominated, but when unilateral, tori were more often found on the right side. Secular changes in the incidence of torus mandibularis among Icelanders suggest the strong influence of environmental factors.     

Plasmodesmatal pores in the torus of bordered pit membranes affect cavitation resistance of conifer xylem

The pit membrane in bordered pits of conifer tracheids is characterized by a porous margo and central thickening (torus), which is traditionally considered to function as an impermeable safety valve against air-seeding. However, electron microscopy based on 33 conifer species, including five families and 19 genera, reveals that pores occur in the torus of 13 of the species studied. The pores have a plasmodesmatal origin with an average diameter of 51 nm and grouped arrangement. Evidence for embolism spreading via pores in tori is supported by the pore sizes, which correspond relatively well with the pressure inducing cavitation. Predictions based on earlier correlations between pit structure and cavitation resistance were only weakly supported for species with punctured tori. Moreover, species with punctured tori are significantly less resistant to cavitation than species with non-punctured tori. Nevertheless, absolute pore diameters must be treated with caution and correlations between theoretical and measured air-seeding pressures are weak. Because most pores appear not to traverse the torus but are limited to one torus pad, only complete pores would trigger air-seeding. Embolism spreading through a leaky torus is not universal across gymnosperms and unlikely to represent the only air-seeding mechanism.     

Mechanism of water‐stress induced cavitation in conifers: bordered pit structure and function support the hypothesis of seal capillary‐seeding

Resistance to water‐stress induced cavitation is an important indicator of drought tolerance in woody species and is known to be intimately linked to the anatomy of the xylem. However, the actual mechanical properties of the pit membrane are not well known and the exact mode of air‐seeding by which cavitation occurs is still uncertain. We examined the relationship between cavitation resistance and bordered pit structure and function in 40 coniferous species. Xylem pressure inducing 50% loss of hydraulic conductance (P₅₀, a proxy for cavitation resistance) varied widely among species, from ?2.9 to ?11.3 MPa. The valve effect of the pit membrane, measured as a function of margo flexibility and torus overlap, explained more variation in cavitation‐resistance than simple anatomical traits such as pit membrane, pit aperture or torus size. Highly cavitation resistant species exhibited both a high flexibility of the margo and a large overlap between the torus and the pit aperture, allowing the torus to tightly seal the pit aperture. Our results support the hypothesis of seal capillary‐seeding as the most likely mode of air‐seeding, and suggest that the adhesion of the torus to the pit border may be the main determinant of cavitation resistance in conifers.     

Soft palate muscle responses to negative upper airway pressure

The afferentpathways and upper airway receptor locations involved in negative upperairway pressure (NUAP) augmentation of soft palate muscle activity havenot been defined. We studied the electromyographic (EMG) response toNUAP for the palatinus, tensor veli palatini, and levator veli palatinimuscles in 11 adult, supine, tracheostomized, anesthetized dogs. NUAPwas applied to the nasal or laryngeal end of the isolated upper airwayin six dogs and to four to six serial upper airway sites from the nasalcavity to the subglottis in five dogs. When NUAP was applied at thelarynx, peak inspiratory EMG activity for the palatinus and tensorincreased significantly (P < 0.05) and plateaued at a NUAP of 10cmH₂O. Laryngeal NUAP failed toincrease levator activity consistently. Nasal NUAP did not increase EMGactivity for any muscle. Consistent NUAP reflex recruitment of softpalate muscle activity only occurred when the larynx was exposed to the stimulus and, furthermore, was abolished by bilateral section of theinternal branches of the superior laryngeal nerves. We conclude thatsoft palate muscle activity may be selectively modulated by afferentactivity originating in the laryngeal and hypopharyngeal airway.     

Stumpy limb--an embryonic lethal mutation in Japanese quail (Coturnix coturnix japonica).

An embryonic lethal mutant was found in Japanese quail and named "stumpy limb (SL)". All SL embryos died at pre-hatching stages, showing brachycephaly, a thickened neck, short upper and lower beaks, and short and thick extremities, while their body length was similar to that of the normal embryos. Observations on the skeleton revealed a globular skull, unusual curvature of the Processus palatinus maxillaris of the upper beak, and shortening and thickening of the appendicular bones. Some embryos showed a bending of the humerus, femur and/or tibiotarsus. Abnormality was more conspicuous in the leg bones than in the wing bones. No conspicuous differences were observed in the vertebrae between the SL and normal embryos. A genetic analysis suggested that the mutation is controlled by an autosomal recessive gene, for which the gene symbol sl was proposed.     

A Study of øX-174 DNA Torus and Lambda DNA Torus Tertiary Structure and the Implications For DNA Self-Assembly

Abstract

Hydrated torus shaped complexes were examined by transmission electron microscopy in both spermidine-condensed linear and nicked circular øX-174 DNA and lambda DNA preparations. Freeze-etch replicas of both these torus samples, produced with very low Pt metal deposition levels (9APt/C), were found to have circumferentially wound single DNA double helix size surface fibers in the range of 30A width. Measurements of torus inner and outer circumference as well as ring thickness were performed. Observed differences in the torus dimension distributions from circular øX-174 DNA and linear øX ?174 DNA may be related to the different topological constraints on DNA folding in these two samples (1). On the basis of annulus thickness measurements øX ?174 DNA toruses, in contrast to lambda DNA toruses, were observed to fall into two classes identified as being formed from monomer DNA condensation and multimer DNA condensation. All of the torus substructure and population dimensions observed here are consistent with the continuous circumferential DNA winding model of torus organization proposed by Marx and Reynolds (1) to explain the micrococcal nuclease cleavage properties of the toruses. End-on view measurements of the torus thickness were made from micrographs obtained by extensive tilting of the object replica. These direct measurements confirmed quaternary structure interpretations made from simple strand packing models. We compared the measured torus properties in this linear DNA size series (5386–48000 bp). With increasing DNA length the pattern of DNA strand self- assembly was found to be more varied producing lambda DNA toruses of varying shape. The relevance of our study to the problem of lambda bacteriophage DNA head packaging was discussed.     

Torus mandibularis in two Northwest Territories Villages

A study of 433 Canadian Eskimos from the villages of Igloolik and Hall Beach, Northwest Territories, revealed an incidence of torus mandibularis of 39.7% in Igloolik and 37.3% in Hall Beach. No statistically significant differences in size or incidence were noted in a comparison of males and females of the two communities. Further, there were no significant differences in the expression and incidence of the torus between the two villages. The incidences noted in these two communities were comparable with the incidences reported for other Eskimos subsisting upon an essentially aboriginal diet but were higher than those previously published for the Wainwright, Alaska, Eskimos who appear to be more acculturated. Studies within the villages indicate that those individuals ingesting a predominately European diet display reduced incidence of the torus when compared with those individuals on a more aboriginal diet.     

Masticatory loading and bone adaptation in the supraorbital torus of developing macaques

Research on the evolution and adaptive significance of primate craniofacial morphologies has focused on adult, fully developed individuals. Here, we investigate the possible relationship between the local stress environment arising from masticatory loadings and the emergence of the supraorbital torus in the developing face of the crab‐eating macaque Macaca fascicularis. By using finite element analysis (FEA), we are able to evaluate the hypothesis that strain energy density (SED) magnitudes are high in subadult individuals with resulting bone growth in the supraorbital torus. We developed three micro‐CT‐based FEA models of M. fascicularis skulls ranging in dental age from deciduous to permanent dentitions and validated them against published experimental data. Applied masticatory muscle forces were estimated from physiological cross‐sectional areas of macaque cadaveric specimens. The models were sequentially constrained at each working side tooth to simulate the variation of the bite point applied during masticatory function. Custom FEA software was used to solve the voxel‐based models and SED and principal strains were computed. A physiological superposition SED map throughout the face was created by allocating to each element the maximum SED value from each of the load cases. SED values were found to be low in the supraorbital torus region throughout ontogeny, while they were consistently high in the zygomatic arch and infraorbital region. Thus, if the supraorbital torus arises to resist masticatory loads, it is either already adapted in each of our subadult models so that we do not observe high SED or a lower site‐specific bone deposition threshold must apply. Am J Phys Anthropol, 2009. © 2008 Wiley‐Liss, Inc.     

Why did the frequency of palatine torus increase in the ancient Anatolian populations?

The frequency of the palatine torus varies in various populations from different regions of the world. In this study, the change of frequency of palatine torus is examined using 387 skulls from 12 different ancient Anatolian populations in various periods ranging from the Early Bronze Age to the first quarter of the 20th century.While the frequency of palatine torus is 45% in the Early Bronze Age, this ratio steadily increases to 87% in the Ottoman Period and finally declines to 40% during the recent period. It was determined that the increase in the frequency of the palatine torus is statistically significant across different periods from the Early Bronze Age until the 20th century. Constituting a passageway between Asia and Europe and being located on the crossroads of the most important trade route of the Medieval Period, the Silk Road, Anatolia is known to have been subjected to recurring invasions and migrations since the 11th century A.D. Therefore, it is possible to say that, with the introduction of the Mongoloid influence in Anatolia, genetic flow has had a significant role in the observed increase in the frequency of this trait.     

Acoustic response properties of single units in the torus semicircularis of the goldfish,Carassius auratus

Single units of the goldfish torus semicircularis (TS) were recorded in response to pure tones. Response areas (RA) were obtained by recording the number of spikes evoked by tones in a range of frequencies and levels within the units' dynamic range. RAs gave estimates of best sensitivity (BS), characteristic frequency (CF), most excitatory frequency at each level (BF), and Q_10dB. Peri-stimulus-time histograms (PSTH), interspike interval histograms (ISIH), and period histograms were obtained at various frequencies and levels to describe the units' temporal response patterns.The distribution of CF is nonuniform with modes at 155, 455, and 855 Hz. The distribution of the coefficient of synchronization to standard tones is also nonuniform, revealing a dichotomy between units with little or no phase-locking and those that phase-lock strongly. PSTHs for units without significant phase-locking vary widely and include patterns resembling those of the mammalian auditory brainstem. Compared with saccular afferents, torus units tend to have lower spontaneous rates, greater sensitivity, and sharper tuning. Unlike saccular afferents, BF is independent of level for most torus units. Some torus units are similar to saccular afferents while others reveal significant transformations of information between the periphery and the midbrain.Abbreviations BF best frequency - BS best sensitivity - CF characteristic frequency - ISIH inter-spike interval histogram - PSTH peri-stimulus-time histogram - RA response area - TS torus semicircularis     

Torus mandibularis in an Alaskan Eskimo population

One of the lowest reported incidences of torus mandibularis (10.7%) in an Eskimo population was observed in the Wainwright, Alaska group studied during 1968. In this population the tori generally did not appear until after the age of 40 years in contrast to other Mongoloid populations previously reported. There was no size difference between males and females, but the males exhibited a much higher incidence of this exostosis. The tori did not significantly increase in size with increasing age after their appearance late in life.     

Evidence for hydrated spermidine-calf thymus DNA toruses organized by circumferential DNA wrapping

In spermidine-condensed calf thymus DNA preparations, torus-shaped condensates were shown by transmission electron microscopy to exist under the hydrated conditions of the freeze fracture experiment. Using extremely low Pt metal deposition levels (9 A Pt/C) high-contrast replicas of the spermidine-DNA toruses were obtained that showed circumferential wrapping of single DNA double helix-size surface fibres. Stereoscopic analysis of high magnification stereomicrographs established some details of the three-dimensional organization of two DNA double helix sections winding circumferentially on the inner surface of one such torus. These measurements demonstrate the usefulness of stereoscopic analysis of these high macromolecular organization magnification. Measurements on a number of torus-shaped complexes (n = 16) yielded these average dimensions: inner circumference (1840 +/- 204 A) outer circumference (2800 +/- 222 A), torus ring thickness (143 +/- 18 A). These data support a continuous circumferential DNA-winding model of torus organization proposed by Marx & Reynolds.