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T Marcel

Publications and source records attributed to T Marcel.

8 recordsLinked to original sources
PubMed1995

Magnetic resonance spectroscopy of the human masseter muscle in nonbruxing and bruxing subjects.

The masseter muscles of six nonbruxing subjects (five men, one woman) and six bruxing subjects (four men, two women) were assessed during chewing by nuclear magnetic resonance spectroscopy (31P-NMR). The NMR spectra were collected on a GE Sigma 1.5T whole body magnet with a double-tuned 31P/1H surface coil. Two-minute trials of rest/chewing/rest were completed three times. Averaged spectra of inorganic phosphate, phosphocreatine, and three adenosine 5' triphosphate peaks were collected in each trial. Bruxing subjects had a lower concentration of total phosphate and phosphocreatine than nonbruxing (control) subjects at rest. Bruxing subjects increased their inorganic phosphate during chewing significantly less than control subjects. The pH levels during rest and during chewing were similar in both controls and bruxers. These preliminary results suggest that bruxing subjects exhibit an altered phosphate metabolism during rest and exhibit a different phosphate metabolism pattern during chewing as compared to nonbruxing subjects.

Adenosine Triphosphate↗
PubMed1990

Patterns of mandibular movements in subjects with craniomandibular disorders.

Mandibular movements were evaluated for border and functional movements in 24 adult normal subjects and 26 adult patients with muscle pain associated with a craniomandibular disorder. The mandibular incisor position was tracked with an electromagnetic system in three planes by use of either a Myotronic Kinesiograph or a Siemens Sirognathograph instrument while the subject sat in an upright position. In the normal subjects, the maximum movements of the mandible in lateral, protrusive, and vertical directions were compared with the envelope of movement during speech and mastication. The range of the rest position was 1 to 5 mm in relation to the intercuspal position; the range of maximum excursion during speech was 30% to 36% of maximum opening; the vertical extent of excursion during mastication was 18% to 90% of the maximum vertical opening dependent on the bolus. Protrusive movements were straight forward, dividing the angle evenly between left and right laterotrusion. Laterotrusive movements were of equal length and similar to the length of protrusion. Twenty-six patients with muscle pain, in many instances, demonstrated asymmetry in the length of laterotrusive movements. Different pathways for moving the mandible away from the intercuspal position and returning to this position could be seen during laterotrusion. Unequal laterotrusive excursions and asymmetrical, nonparallel movement patterns for mandibular protrusion and retrusion were often observed. In contrast, the extent of the speech envelope and the envelope of mastication were similar to that of the controls.

Adolescent↗
PubMed1990

Nucleotide sequence and organization of the upstream region of the Corynebacterium glutamicum lysA gene.

Maximum expression of the Corynebacterium glutamicum lysA gene is dependent upon the presence of a 2.3 kb region immediately 5' of the lysA reading frame. Subcloning and functional analysis of the upstream region implied that this region contained the lysA promoter. Sequence determination of the upstream region revealed a single open reading frame, orfX, in the same orientation as lysA. The orfX coding sequence exhibited all the sequence characteristics of a gene with the potential for a 550-amino-acid polypeptide product. Expression of lysA is coupled to that of orfX via a common promoter located immediately 5' of orfX. The RNA start site has been determined by S1 nuclease mapping. Both the orfX and the lysA gene are expressed as a single 3.0 kb RNA transcript. These data indicate that orfX and lysA are genes within a two-gene operon. Expression of the lysA gene is not subject to regulation by lysine. The orfX gene product was shown not to be directly linked to the lysine biosynthetic pathway, nor is it the enzyme incorporating DAP into the peptidoglycan precursor.

Amino Acid Sequence↗
PubMed1988

Characterization of crystals of xylose isomerase from Streptomyces violaceoniger.

Crystals of the tetrameric xylose isomerase from Streptomyces violaceoniger have been examined by x-ray analysis. Octahedral crystals with a maximum dimension of 0.7 mm were grown from ammonium sulfate solution. They possess the symmetry of P4(1)2(1)2 or P4(3)2(1)2 space groups, which are crystallographically indistinguishable. The unit cell dimensions are a = b = 140 A and c = 134 A. There is one tetramer of molecular weight 160,000 per asymmetric unit. The crystals diffract to 2.2 A.

Aldose-Ketose Isomerases↗