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Biomedical subjects

B Solow

Publications and source records attributed to B Solow.

At least 19 recordsLinked to original sources
PubMed2001

Temporomandibular disorders in relation to craniofacial dimensions, head posture and bite force in children selected for orthodontic treatment.

The present study examined the associations between craniofacial dimensions, head posture, bite force, and symptoms and signs of temporomandibular disorders (TMD). The sample comprised 96 children (51F, 45M) aged 7-13 years, sequentially admitted for orthodontic treatment of malocclusions entailing health risks. Symptoms and signs of TMD were assessed by 37 variables describing the occurrence of headache and facial pain, clicking, jaw mobility, tenderness of muscles and joints, and the Helkimo Anamnestic and Dysfunction indices. Craniofacial dimensions (33 variables), and head and cervical posture (nine variables) were recorded from lateral cephalometric radiographs taken with the subject standing with the head in a standardized posture (mirror position). Dental arch widths were measured on plaster casts and bite force was measured at the first molars on each side by means of a pressure transducer. Associations were assessed by Spearman correlations and multiple stepwise logistic regression analyses. The magnitudes of the significant associations were generally low to moderate. On average, temporomandibular joint (TMJ) dysfunction was seen in connection with a marked forward inclination of the upper cervical spine and an increased craniocervical angulation, but no firm conclusion could be made regarding any particular craniofacial morphology in children with symptoms and signs of TMJ dysfunction. Muscle tenderness was associated with a 'long face' type of craniofacial morphology and a lower bite force. Headache was associated with a larger maxillary length and increased maxillary prognathism. A high score on Helkimo's Clinical Dysfunction Index was associated with smaller values of a number of vertical, horizontal, and transversal linear craniofacial dimensions and a lower bite force.

Adolescent↗
PubMed2001

Bite force in pre-orthodontic children with unilateral crossbite.

In the present study bite force was examined in pre-orthodontic children with unilateral posterior crossbite and compared with an age- and sex-matched control group. The sample comprised 52 children aged 7-13 years, 26 pre-orthodontic children with unilateral posterior crossbite (crossbite group), and 26 children with neutral occlusion (control group). Unilateral bite force was measured at the first molar by means of a pressure transducer. Furthermore, symptoms and signs of temporomandibular disorders (TMD) and number of teeth in contact in the intercuspal position (ICP) were recorded. In both groups, the maximum bite force increased significantly with age and with increasing stages of dental eruption, but the bite force in both sexes did not differ significantly. There were no significant differences in bite force between sides, but this was significantly smaller in the crossbite group than in the controls (P < 0.001). Regression analysis showed that stage of dental eruption (P < 0.001), number of teeth in occlusal contact (P < 0.01), and unilateral crossbite (P < 0.001) were the only variables significantly correlated with bite force. The number of teeth in contact was significantly smaller in the crossbite group than in the controls (P < 0.05) and the frequency of muscle tenderness was significantly higher in the crossbite group than in the controls (P < 0.05). These results suggest that differences in the muscle function associated with unilateral crossbite lead to a significantly smaller bite force in the crossbite group compared with controls and this difference did not diminish with age and development. These findings indicate that early treatment of unilateral posterior crossbite is advisable to optimize conditions for function.

Adolescent↗
PubMed2000

Change in the width of the mandibular body from 6 to 23 years of age: an implant study.

After the ossification of the mandibular symphysis, shortly after birth, changes in mandibular width would be expected to occur only by surface apposition or resorption on the buccal surfaces of the left and right mandibular halves. However, evidence for an opening hinge movement of the two mandibular halves around a vertical axis located in the region of the mandibular symphysis was recently found in longitudinal studies of 29 subjects with unilateral implant markers in the mandible. These subjects were followed from 8.5 to 15.5 years of age (Korn and Baumrind, 1990; Baumrind and Korn, 1992). The aim of the present investigation was to examine whether the presence of such an age-related increase in mandibular body width could be confirmed in a sample with bilateral implant markers in the mandible. The sample comprised 10 subjects (3F, 7M) from the files of another longitudinal study with implant markers (Björk, 1968). A total of 122 pairs of annual lateral and postero-anterior (p-a) cephalometric records were available, covering longitudinal observation periods ranging from 8 to 16 years within an age interval of between 6 and 23 years. The width between a right and left side mandibular implant marker was measured with digital callipers on all p-a radiographs. Each measurement was corrected mathematically for various sources of radiographic enlargement. A small, but statistically significant increase in the distance between the right and left implant markers, i.e. in the bilateral width of the mandibular body, was observed in all subjects. The total increase in width in each subject ranged from 0.7 to 1.7 mm for the various periods of observation (P < or = 0.01). For the 12-year period from 6 to 18 years, the average total increase was 1.6 mm (P < or = 0.001, SD = 0.42), i.e. 0.13 mm/year. After this age there was no systematic trend. The mechanism for this increase in width is unknown. It is suggested that during postnatal growth, an increasing load from the masticatory occlusal forces might influence endosteal bone remodelling in the mandibular body, thus producing or allowing a gradual permanent outward bending of the right and left mandibular halves.

Adolescent↗
PubMed1999

The functional shift of the mandible in unilateral posterior crossbite and the adaptation of the temporomandibular joints: a pilot study.

Changes in the functional shift of the mandibular midline and the condyles were studied during treatment of unilateral posterior crossbite in six children, aged 7-11 years. An expansion plate with covered occlusal surfaces was used as a reflex-releasing stabilizing splint during an initial diagnostic phase (I) in order to determine the structural (i.e. non-guided) position of the mandible. The same plate was used for expansion and retention (phase II), followed by a post-retention phase (III) without the appliance. Before and after each phase, the functional shift was determined kinesiographically and on transcranial radiographs by concurrent recordings with and without the splint. Transverse mandibular position was also recorded on cephalometric radiographs. Prior to phase I, the mandibular midline deviated more than 2 mm and, in occlusion (ICP), the condyles showed normally centred positions in the sagittal plane. With the splint, the condyle on the crossbite side was displaced 2.4 mm (P < 0.05) forwards compared with the ICP, while the position of the condyle on the non-crossbite side was unaltered. After phase III, the deviation of the midline had been eliminated. Sagittal condylar positions in the ICP still did not deviate from the normal, and the splint position was now obtained by symmetrical forward movement of both condyles (1.3 and 1.4 mm). These findings suggest that the TMJs adapted to displacements of the mandible by condylar growth or surface modelling of the fossa. The rest position remained directly caudal to the ICP during treatment. Thus, the splint position, rather than the rest position should be used to determine the therapeutic position of the mandible.

Adaptation, Physiological↗
PubMed1998

Archael phosphoproteins. Identification of a hexosephosphate mutase and the alpha-subunit of succinyl-CoA synthetase in the extreme acidothermophile Sulfolobus solfataricus.

When soluble extracts from the extreme acidophilic archaeon Sulfolobus solfataricus were incubated with [gamma-32P]ATP, several radiolabeled polypeptides were observed following SDS-PAGE. The most prominent of these migrated with apparent molecular masses of 14, 18, 35, 42, 46, 50, and 79 kDa. Phosphoamino acid analysis revealed that all of the proteins contained phosphoserine, with the exception of the 35-kDa one, whose protein-phosphate linkage proved labile to strong acid. The observed pattern of phosphorylation was influenced by the identity of the divalent metal ion cofactor used, Mg2+ versus Mn2+, and the choice of incubation temperature. The 35- and 50-kDa phosphoproteins were purified and their amino-terminal sequences determined. The former polypeptide's amino-terminal sequence closely matched a conserved portion of the alpha-subunit of succinyl-CoA synthetase, which forms an acid-labile phosphohistidyl enzyme intermediate during its catalytic cycle. This identification was confirmed by the ability of succinate or ADP to specifically remove the radiolabel. The 50-kDa polypeptide's sequence contained a heptapeptide motif, Phe/Pro-Gly-Thr-Asp/Ser-Gly-Val/Leu-Arg, found in a similar position in several hexosephosphate mutases. The catalytic mechanism of these mutases involves formation of a phosphoseryl enzyme intermediate. The identity of p50 as a hexosephosphate mutase was confirmed by (1) the ability of sugars and sugar phosphates to induce removal of the labeled phosphoryl group from the protein, and (2) the ability of [32P]glucose 6-phosphate to donate its phosphoryl group to the protein.

Adenosine Diphosphate↗
PubMed1998

Malocclusion traits and symptoms and signs of temporomandibular disorders in children with severe malocclusion.

The present study reports the prevalence of the various traits of malocclusion, as well as the occurrence of associations between malocclusion, and symptoms and signs of temporomandibular disorders (TMD) in children selected for orthodontic treatment by the new Danish procedure for screening the child population for severe malocclusions entailing health risks. The sample comprised 104 children (56 F, 48 M) aged 7-13. Malocclusion traits were recorded at the time of selection, symptoms and signs of TMD were recorded at recall. The most prevalent malocclusion traits were distal molar occlusion (Angle Class II; 72 per cent), crowding (57 per cent), extreme maxillary overjet (37 per cent) and deep bite (31 per cent). Agenesis or peg-shaped lateral teeth were observed in 14 per cent of the children. The most prevalent symptom of TMD was weekly headache (27 per cent); the most prevalent signs of TMD were tenderness in the anterior temporal, occipital, trapezius, and superficial and profound masseter muscles (39-34 per cent). Seven per cent of the children were referred for TMD treatment. The Danish TMD screening procedure was positive in 26 per cent, while 20 per cent had severe symptoms (Aill), and 30 per cent had moderate signs (Dill) according to Helkimo (1974). Symptoms and signs of TMD were significantly associated with distal molar occlusion, extreme maxillary overjet, open bite, unilateral crossbite, midline displacement, and errors of tooth formation. The analysis suggests that there is a higher risk of children with severe malocclusions developing TMD. Errors of tooth formation in the form of agenesis or peg-shaped lateral teeth showed the largest number of associations with symptoms and signs of TMD; these associations have not previously been reported in the literature.

Adolescent↗
PubMed1998

Head posture and malocclusions.

The present study aimed to examine whether any pattern of associations could be found between the posture of the head and neck, and the occurrence of malocclusions. The sample comprised 96 children (45 M, 51 F) aged 7-13 years, sequentially admitted for orthodontic treatment of severe malocclusions. Malocclusions were diagnosed clinically and classified into occlusal, spacing, and dentitional anomalies and their subdivisions. Craniovertical, craniocervical, and cervicohorizontal postural variables were recorded from lateral cephalometric radiographs taken with the subject standing with the head in the natural head position (mirror position). A clear pattern of associations between crowding and craniocervical posture was found. Subjects with anterior crowding, i.e. more than 2 mm lack of space in the upper or lower anterior segments of the dental arch, had craniocervical angles that were on average 3-5 degrees larger than subjects without crowding (P < 0.05, P < 0.01). The findings were in agreement with the soft tissue stretching hypothesis, according to which the sagittal development of the dentoalveolar arches is impeded by the increased dorsally-directed soft tissue pressure in subjects with extended craniocervical posture.

Adolescent↗
PubMed1997

Biosynthesis of the peptide bond in the coenzyme N-(7-mercaptoheptanoyl)-L-threonine phosphate.

The biochemical mechanism for the formation of the amide bond in N-(7-mercaptoheptanoyl)-L-threonine phosphate (HS-HTP) has been studied by measuring the incorporation of L-[3-(3)H]threonine into N-(7-mercaptoheptanoyl)-L-threonine (HS-HT) by cell extracts (CE) of Methanosarcina thermophila incubated with different precursors. Synthesis of HS-HT was observed from L-[3-(3)H]threonine and 7-mercaptoheptanoic acid (HS-H) when the incubations were conducted with either crude CE or Sephadex column-purified CE. In the presence of CE, the synthesis of HS-HT was found to be inhibited 66% by preincubation of the extract with ATPase, indicating that ATP was involved in the biosynthesis. In spite of this indication of ATP involvement in the coupling reaction, incubation of the crude CE with L-[3-(3)H]threonine, HS-H, and ATP was found to inhibit the formation of HS-HT. In contrast, the synthesis of HS-HT in the presence of Sephadex column-purified CE was found to be stimulated by the addition of ATP. Incubation of the crude CE with the CoA thioester of 7-mercaptoheptanoic acid (HS-HCoA) or the mixed disulfide formed between coenzyme M and 7-mercaptoheptanoic acid did not stimulate the biosynthesis. The biosynthesis of HS-HT was found to be strongly inhibited by an ethanol extract of the crude CE. This inhibition was found to be attributed to the HS-HTP present in the extract. Stimulation of HS-HT biosynthesis 300-fold was observed when the Sephadex column-purified CE was incubated with L-[3-(3)H]threonine and 7-mercaptoheptanoyl phosphate (HS-H-P). Data indicate that HS-HT is produced by the phosphorylation of HS-H to HS-H-P with ATP, which then reacts with L-threonine to produce HS-HT.

Adenosine Triphosphate↗
PubMed1997

Gene cloning and expression and characterization of a toxin-sensitive protein phosphatase from the methanogenic archaeon Methanosarcina thermophila TM-1.

With oligonucleotides modelled after conserved regions within the protein-serine/threonine phosphatases (PPs) of the PP1/2A/2B superfamily, the gene for the archaeal protein phosphatase PP1-arch2 was identified, cloned, and sequenced from the methanogenic archaeon Methanosarcina thermophila TM-1. The DNA-derived amino acid sequence of PP1-arch2 exhibited a high degree of sequence identity, 27 to 31%, with members of the PP1/2A/2B superfamily such as PP1-arch1 from Sulfolobus solfataricus, PP1alpha from rats, PP2A from Saccharomyces cerevisiae, and PP2B from humans. The activity of the recombinant PP1-arch2 was sensitive to several naturally occurring microbial toxins known to potently inhibit eucaryal PP1 and PP2A, including microcystin-LR, okadaic acid, tautomycin, and calyculin A.

Acetates↗
PubMed1996

Cloning of a potential cytochrome P450 from the archaeon Sulfolobus solfataricus.

Abstract A gene, CYP119, for a potential cytochrome P450 has been isolated and sequenced from the extreme acidothermophilic archaeon Sulfolobus solfataricus. The gene predicts a polypeptide of 368 amino acids containing the consensus heme-binding sequence Phe-Gly-Xaa-Gly-Xaa-His-Xaa-Cys-Xaa-Gly- Xaa3-Ala-Arg-Xaa-Glu. It most closely resembles the cytochrome P450s found in the bacterium Bacillus subtilis, with which it shares 129 identical amino acid residues (35%). This first sequence of a potential archaeal cytochrome P450 represents an important step in tracing the complex evolutionary history of this biologically important enzyme family.

Amino Acid Sequence↗
PubMed1996

Continued eruption of maxillary incisors and first molars in girls from 9 to 25 years, studied by the implant method.

The aim of this study was to describe the average and individual patterns of continued eruption of the maxillary incisors and first molars in a longitudinal sample of girls. The sample comprised 14 series of lateral cephalometric films of girls, obtained from the archives of the implant study of Björk (1968). All subjects had bilateral posterior maxillary implants and one or two anterior maxillary implants. Subjects with craniofacial anomalies were excluded. The sample represented various types of malocclusions, but records during periods of orthodontic treatment were excluded from the calculation of average data and average curves. The final sample comprised 147 radiographs in the age range 9-25 years. Data were debugged by comprehensive numerical and graphical procedures. The average cumulative continued eruption from 9-25 years of age was 6 mm downwards and 2.5 mm forwards for the upper incisors, and 8 mm downwards and 3 mm forwards for the upper first molars. This resulted in an average reduction of the occlusal plane inclination (OLs/IPLs) of 4.5 degrees from 9-16 years. Attention is drawn to the fact that due to the continued eruption of the natural teeth, the use of osseointegrated implants with artificial teeth should not be recommended in childhood, adolescence, and early adulthood, unless special provision is made for later revision or replacement of the artificial teeth to compensate for the lack of continued eruption of such implants.

Adolescent↗
PubMed1996

Airway dimensions and head posture in obstructive sleep apnoea.

The present cephalometric study aimed to describe the antero-posterior diameters of the pharyngeal airway in a sample of 50 male obstructive sleep apnoea (OSA) patients and a reference sample of 103 male students, and to examine the relationship between these diameters and the posture of the head and the cervical column. Subjects were recorded in the cephalometer standing with the head in its natural position (mirror position). Pharyngeal airway diameters were measured at seven levels ranging from the maxillary tuberosity to the vallecula of the epiglottis. The largest difference was observed at the level behind the soft palate where the diameter was 50 per cent narrower in the OSA sample than in the reference sample. Extension of the cranio-cervical angle and forward inclination of the cervical column were correlated with an increase in the three most caudal airway diameters in the OSA sample: at the uvula, the root of the tongue, and the epiglottis, but only to increase in the lowest diameter in the reference sample. The findings were considered to reflect a compensatory physiological postural mechanism that serves to maintain airway adequacy in OSA patients in the awake erect posture, most efficiently so at the lowest levels of the oropharyngeal airway.

Adult↗
PubMed1995

The adenoid as a key factor in upper airway infections.

The adenoids (and the nasopharynx) play a key role in the normal functioning and in various pathologies of the upper respiratory tract. In this paper the role of adenoidal pathology and the beneficial effect of adenoidectomy in some upper respiratory tract and facial anomalies and diseases are discussed; otitis media with effusion, recurrent acute otitis media, sinusitis, snoring and sleep apnea and abnormal patterns in the midface growth and development.

Adenoidectomy↗
PubMed1995

Average surface remodeling of the maxillary base and the orbital floor in female subjects from 8 to 25 years. An implant study.

The present study aimed to analyze the surface remodeling of the maxilla by the method of metallic implants. The sample comprised 14 series of lateral cephalometric films of girls, and was derived from the files of the implant study of Björk. Implants had been inserted below the anterior nasal spine and on the lower anterior surfaces of the zygomatic arches. Various types of malocclusion were represented in the sample, but records during periods of orthodontic treatment and retention were excluded from the analysis. No subjects with craniofacial anomalies were included. The final sample comprised 155 radiographs in the age range 8 to 25 years. In addition to the anatomically defined reference points, six fiducial points and two implant points in the maxilla were digitized from each film. Data were debugged by comprehensive numerical and graphical procedures. The average relocation of the reference point subspinale (ss, Down's A point) was about 4.5 mm down and 0.5 mm forward from 8 to 25 years, whereas the reference point spinal (sp, ANS) was relocated about 4.5 mm down and 1 mm forward. The reference point pterygomaxillare (pm, PNS) was relocated 6 mm backward and 1.5 mm down by surface remodeling. The relocation of the sp and pm points resulted in an angular remodeling of the palatal plane of 2.5 degrees (backward). At the same time the maxillary complex rotated -1.5 degrees (forward) in relation to the anterior cranial base, resulting in a 1 degrees increase in the inclination of the palatal plane to the anterior cranial base. The orbital floor showed an average relocation of about 2.5 mm up and 2 mm backward by surface apposition, partly masking both the downward and forward sutural translation and the average forward growth rotation of the maxilla. Because of the angular remodeling of the palatal plane and the surface apposition on the hard palate, it is recommended that great caution be exerted in the interpretation of clinical treatment analyses based on superimposition on lines or structures defined by the anatomy of the bony palate during the period of growth.

Adolescent↗
PubMed1994

Craniofacial morphology in patients with multiple congenitally missing permanent teeth.

The purpose of this study was to examine the association between the number of congenitally missing permanent teeth, excluding third molars, and the craniofacial morphology. The sample comprised 118 children with five or more congenitally missing teeth. Twenty-seven reference points were digitized from lateral cephalometric radiographs and 13 angular measurements of craniofacial morphology were calculated. After an initial analysis, the sample was divided into two subsamples, one with 5-12 missing teeth and the other with 13-21 missing teeth. Within each subsample there was no significant association between number of missing teeth and the angular variables, but a comparison between the two subsamples showed significantly smaller mandibular plane inclination (NSL/ML, NL/ML) and gonial angle (RL/ML), and a more prognathic mandible (s-n-pg) in the subsample with more than 12 teeth missing. It is suggested that the difference in morphology could be due to a reduced vertical development of the lower face, caused by a reduced occlusal support in the subsample with more than 12 congenitally missing teeth.

Adolescent↗
PubMed1994

Atlas morphology in relation to craniofacial morphology and head posture.

The associations between dimensions of the first cervical vertebra, atlas, and a representative set of craniofacial and postural variables were studied on cephalometric radiographs of a sample of 103 adult males aged 22-30 years, recorded in the natural head position (mirror position). Atlas morphology was expressed by nine variables, linear and angular craniofacial dimensions by 27 variables, and head and cervical posture by seven variables. A pattern of low but significant correlations was found. Although the correlations were low, the study confirmed that the dimensions of the atlas vertebra reflect associations between cranio-cervical posture and craniofacial morphology. Negative correlations were found between the height of the posterior arch of atlas and the inclination of the mandible and the maxilla to the anterior cranial base. Low positive correlations between the height of the anterior arch and vertical facial dimensions reflect the general co-ordination of the vertical growth of the face and the cervical column. Moreover, the pattern of correlations between the atlanto-cranial angle and facial morphology suggests that in changes of the cranio-cervical angle, atlas follows the cervical column.

Adult↗
PubMed1993

Head posture in obstructive sleep apnoea.

In growing subjects, obstruction of the upper airway may lead to excessive vertical facial development. According to the soft-tissue stretching hypothesis (Solow and Kreiborg, 1977) this could be due to an increased cranio-cervical angulation triggered by the airway obstruction. The present study aimed to examine the effect of airway obstruction on cranio-cervical posture in a sample of adult patients with severe obstructive sleep apnoea (OSA). Lateral cephalometric radiographs taken in the natural head position (mirror position) were obtained from 50 male patients aged 28-70 with polysomnographic diagnosis of obstructive sleep apnoea. The Apnoea Index ranged from 21 to 98 episodes per hour with a mean of 54.6. Control samples were available from previous cephalometric studies of head posture in five samples of healthy subjects and one sample of congenitally blind subjects. The average cranio-cervical angle, NSL/OPT, was found to be extremely large (mean 104.1, SD 9.1) exceeding the average values in the control samples by 1-2 standard deviations (P < 0.001). It is suggested that the large cranio-cervical angle in OSA patients is a physiological adaptation aiming to maintain airway adequacy while the head, and thus the visual axis, is kept in its natural relationship to the true vertical. The findings thus provide evidence for the hypothesis that upper airway obstruction may trigger an increase in the cranio-cervical angulation.

Adaptation, Physiological↗