Methionine depletion induces transcription of the mRNA (N6-adenosine)methyltransferase.

This study examines the genetic expression of the S-adenosyl-L-methionine binding subunit of the mRNA (N6-adenosine)methyltransferase (MT-A70) in cultured cells under conditions known to affect transmethylation reactions. Methionine dependence, disrupted methionine metabolism, and increased transmethylation reactions are all phenotypes characteristic of cancer cells. The results show that both methionine depletion and inhibition of S-adenosyl-L-methionine formation can induce up to a four-fold increase in transcription of this S-adenosyl-L-methionine binding subunit. The two splice-variant mRNAs produced from the MT-A70 gene are transcribed at different rates depending on the level of S-adenosyl-L-methionine inhibition. This result may reflect differing Km values toward the substrate for the different enzyme isoforms. 3-Deazaadenosine, an inhibitor known to block certain mRNA transmethylations, was shown to have no effect on MT-A70 gene expression. This result indicates that the control of MT-A70 gene expression is directly related to methionine availability and the subsequent synthesis of S-adenosyl-L-methionine.

Expression of the mRNA (N6-adenosine)-methyltransferase S-adenosyl-L-methionine binding subunit mRNA in cultured cells.

Ribonuclease protection assays (RPA) were used to detect and quantitate the amount of messenger RNA (mRNA) coding for the S-adenosyl-L-methionine binding subunit (MT-A70) of the mRNA (N6-adenosine)-methyltransferase from different types of cultured cells. HeLa cells cultured in suspension were analyzed at regular intervals along a normal growth curve. It was discovered that MT-A70 mRNA was transcribed constitutively across the time-course, irrespective of the rate of cellular proliferation. Further, 11 different cell lines representing non-tumorigenic, tumorigenic, and virally-transformed tumorigenic types from Homo sapiens, Mus musculus, and Rattus norvegicus were examined for MT-A70 mRNA expression. It was found that all the cell lines expressed a long and short splice-variant form of the gene. In general, the cell lines expressed a similar total amount of the MT-A70 mRNA while statistically significant differences existed between the quantity of the long and short forms among cell types. Tumorigenic cell lines synthesized as much as a 9-fold greater amount of long form versus short form MT-A70 mRNA. Comparatively, non-tumorigenic cell lines generally expressed only a 1.5-fold greater amount of long form versus short form MT-A70 mRNA.

Internal 6-methyladenine residues increase the in vitro translation efficiency of dihydrofolate reductase messenger RNA.

N6-Methyladenosine (m6A) is found internally in a number of mRNA molecules from higher eucaryotic cells. In these investigations, it was found that the presence of m6A residues increase the in vitro translation efficiency of capped T7 transcripts of mouse dihydrofolate reductase (DHFR) mRNA. Using an in vitro rabbit reticulocyte translation system, the formation of internal m6A residues in the DHFR transcripts resulted in a 1.5-fold increase in translated DHFR compared to transcripts void of internal m6A residues. Translation in a wheat germ system, however, resulted in no increase in translation efficiency upon m6A formation, suggesting that the mechanism may be species-specific.

Correlates of myoelectric asymmetry detected in low back pain patients using hand-held post-style surface electromyography.

OBJECTIVE: Paraspinal surface electromyographic (SEMG) scanning, utilizing post-style hand-held electrodes, was conducted to determine the usefulness of the technique as an assessment for myoelectric indicators of low back pain (LBP). A secondary objective was to correlate myoelectric abnormalities with other known outcome measures of the manipulable lesion. DESIGN: Blinded SEMG assessments with the patients standing upright, fully flexed and extended at the trunk, and measures of pressure pain thresholds (PPT) were made after four tests administered by another examiner. SETTING: The research was conducted on patients in a private chiropractic practice. PATIENTS: A convenience sample of 10 of the practitioner's most acute LBP patients without neurological deficit were asked to participate and none refused. Six patients without recent LBP volunteered as controls. MAIN OUTCOME MEASURES: Preset myoelectric indicators included: thoracolumbar asymmetry (T-L/A: first seen in an earlier pilot study), loss of flexion/relaxation (F/R) at L3, contralateral responsivity (increased myoelectric activity opposite the side of leg pain) and right/left asymmetry (R-L/A) at L3. RESULTS: Significant differences between groups were seen in T-L/A (p = .04) and R-L/A [data averaged from three postures (p = .04)], and robust group differences were seen in F/R (p = .011 right; p = .026 left). Contralateral responsivity was not significant. Loss of F/R was the only indicator that correlated with diminished PPT (r = .52 right; r = .46 left) and with Oswestry disability (r = .42), and that negatively correlated, as expected, with straight leg raising (r = -.50 right; r = -.74 left). CONCLUSIONS: Results support use of the technique to detect muscle dysfunction related to LBP. Further research of SEMG correlations with measures of the manipulable lesion is warranted.

An evaluation of chiropractic manipulation as a treatment of hyperactivity in children.

The principle aim of this study was to determine the effectiveness of chiropractic manipulative therapy in the treatment of children with hyperactivity. Using blinds between investigators and a single subject research design, the investigators evaluated the effectiveness of the treatment for reducing activity levels of hyperactive children. Data collection included independent evaluations of behavior using a unique wrist-watch type device to mechanically measure activity while the children completed tasks simulating school-work. Further evaluations included electrodermal tests to measure autonomic nervous system activity. Chiropractic clinical evaluations to measure improvement in spinal biomechanics were also completed. Placebo care was given prior to chiropractic intervention. Data were analyzed visually and using nonparametric statistical methods. Five of seven children showed improvement in mean behavioral scores from placebo care to treatment. Four of seven showed improvement in arousal levels, and the improvement in the group as a whole was highly significant (p = 0.009). Agreement between tests was also high in this study. For all seven children, three of the four principal tests used to detect improvement were in agreement either positively or negatively (parent ratings of activity, motion recorder scores, electrodermal measures, and X-rays of spinal distortions). While the behavioral improvement taken alone can only be considered suggestive, the strong interest agreement can be taken as more impressive evidence that the majority of the children in this study did, in fact, improve under specific chiropractic care. The results of this study, then, are not conclusive, however, they do suggest that chiropractic manipulation has the potential to become an important nondrug intervention for children with hyperactivity. Further investigation in this area is certainly warranted.

Technologist shortage in hospitals: what's going on here?

In many parts of the United States, the current economic and political environment has created a shortage of qualified radiologic technologists willing to work in hospitals. This article discusses the causes, effects and suggested remedies for this shortage.

The multiple baseline across subjects design: proposed use in research.

This paper examines the use of single-subject research methodology in clinical research. Specifically, the use of the multiple baseline design across subjects is discussed relative to its application to chiropractic research. Brief discussion of the history of the development of single-subject research methodology is presented along with discussions of its strengths and weaknesses, issues related to its use, and some of the fields in which it has been utilized. The multiple baseline design across subjects is described and explained and an illustrative example of its application to a field based chiropractic research problem is provided. Finally, the advantages of this methodology for a field such as chiropractic, largely dependent upon the scientist-practitioner model, are discussed.

An evaluation of the effect of chiropractic manipulative therapy on hypolordosis of the cervical spine.

Cervical curve depth (CCD) was radiographically evaluated in 35 patients who presented with cervical hypolordosis or kyphosis (CH/K). Of these, one group of 20 patients received chiropractic manipulative therapy (CMT) for the purpose of correcting the disorder. A second group of nine patients received both CMT and an orthopedic cervical pillow for in home correction of the CH/K. A control group of six patients received CMT which was not intended to correct the CH/K. The purpose of the study was to determine the efficacy of CMT in the correction of CH/K. Analysis of the data indicated that CMT is significantly effective in the treatment of CH/K. There was a mean improvement of 4.55 degrees (p less than 0.01) in the group receiving only CMT, as assessed by CCD radiographic analysis. There was also significant improvement of 2.22 degrees (p less than 0.05) in the group receiving both CMT and orthopedic cervical pillow therapy. The findings lend support to fundamental chiropractic tenets such as that spinal manipulation is beneficial in correcting biomechanical disorders of the spine. Specifically, the study documents the role of chiropractic care in the correction of CH/K as may result from postural, musculoligamentous, or traumatic etiology such as the so-called "whiplash" injury.