Quantitative in situ hybridization for peptide mRNAs in mouse brain.

The objective was to determine the feasibility of using a radioactive capture method (Fuji FLA 2000) and image analysis system for the measurement of peptide mRNA levels in specific brain regions in mice. As a test mRNA, we chose vasopressin (VP) and oxytocin (OT) because they are expressed in abundance in the hypothalamic paraventricular (PVN) and supraoptic nuclei (SON). A comparison was made between free-floating and slide-mounted sections to determine which method yielded better results. Mouse brains were fixed in 4% paraformaldehyde (PFA) and processed for in situ hybridization using 35S-oligonucleotide probes for VP and OT. After overnight hybridization and high stringency washes, 25-microm brain sections and 14C standards were exposed to a BAS-IIIs Fuji imaging film over a range of times (4 h-6 days). Results showed that there was an intense hybridization reaction in the PVN and SON, making it possible to distinguish the specific brain regions. Using Image Gauge Software, the signal was quantified in PVN and SON. A comparison of the different exposure times showed that the signal could be measured after as little as 4 h. The intensity readings increased over time while the calculated radioactivity remained constant. The free-floating method was superior to the slide-based system, providing a lower background and a higher signal. The data illustrates the applicability of the phosphor imaging system for the reproducible measurement of mRNA levels in discrete regions of the mouse brain.

A meta-analysis of clinical trials of spinal manipulation.

OBJECTIVE: To assess the efficacy of spinal manipulative therapy (SMT) in the treatment of back pain using meta-analytical techniques. DATA SOURCES: The literature was systematically searched for all studies of SMT through June 1989. The Index Medicus from 1980 was expanded by citation tracking. The Chiropractic Research Archives Collection was utilized as a regularly updated bibliographic source for the location of research publications. A hand search of professional chiropractic journals was also undertaken. STUDY SELECTION: Studies in English with concurrent controls treated by methods other than SMT, including sham, produced 23 randomized controlled clinical trials of the effectiveness of spinal manipulation. Because a single trial might include more than one comparison of treatments, these trials produced a total of 34 mutually exclusive, discrete samples. DATA EXTRACTION: Data were extracted via a standardized coding document by one author and verified by two of the others. Data were independently extracted from a subset of the studies by a blinded research assistant to ensure that coding methods produced acceptable consistency. DATA SYNTHESIS: Effect sizes (Cohen's D index) were calculated for nine outcome variables at eight time points following the initiation of treatment. Thirty-eight of 44 effect sizes indicated that SMT was better than the comparison treatment. It was also found that meta-analysis was an imperfect instrument for the kind of trials that were pooled in this study because the research protocols were highly diverse. Furthermore, because the nature of SMT does not permit an easy use of placebos, true no-treatment control groups were rare. Most studies compared SMT to an alternative treatment. This probably obscured the effectiveness of SMT since the comparison treatments were presumably also effective. CONCLUSIONS: SMT proved to be consistently more effective in the treatment of low back pain than were any of the array of comparison treatments. The analysis provided some suggestion that manipulation, as such, is more effective than mobilization, as such. For the future, it is suggested that researchers strive for more consistent measures in terms of explicit descriptions of the nature of SMT, the times of post-treatment assessments and the nature of outcome measures. Only then can meta-analysis fulfill its potential in this clinical area.