Hapten-derivatized nanoparticle targeting and imaging of gene expression by multimodality imaging systems.

Non-invasive gene monitoring is important for most gene therapy applications to ensure selective gene transfer to specific cells or tissues. We developed a non-invasive imaging system to assess the location and persistence of gene expression by anchoring an anti-dansyl (DNS) single-chain antibody (DNS receptor) on the cell surface to trap DNS-derivatized imaging probes. DNS hapten was covalently attached to cross-linked iron oxide (CLIO) to form a 39+/-0.5 nm DNS-CLIO nanoparticle imaging probe. DNS-CLIO specifically bound to DNS receptors but not to a control single-chain antibody receptor. DNS-CLIO (100 microM Fe) was non-toxic to both B16/DNS (DNS receptor positive) and B16/phOx (control receptor positive) cells. Magnetic resonance (MR) imaging could detect as few as 10% B16/DNS cells in a mixture in vitro. Importantly, DNS-CLIO specifically bound to a B16/DNS tumor, which markedly reduced signal intensity. Similar results were also shown with DNS quantum dots, which specifically targeted CT26/DNS cells but not control CT26/phOx cells both in vitro and in vivo. These results demonstrate that DNS nanoparticles can systemically monitor the expression of DNS receptor in vivo by feasible imaging systems. This targeting strategy may provide a valuable tool to estimate the efficacy and specificity of different gene delivery systems and optimize gene therapy protocols in the clinic.

A membrane antibody receptor for noninvasive imaging of gene expression.

Monitoring gene expression is important to optimize gene therapy protocols and ensure that the proper tissue distribution is achieved in clinical practice. We developed a noninvasive imaging system based on the expression of artificial antibody receptors to trap hapten-labeled imaging probes. Functional membrane-bound anti-dansyl antibodies (DNS receptor) were stably expressed on melanoma cells in vitro and in vivo. A bivalent (DNS)2-diethylenetriaminepentaacetic 111Indium probe specifically bound to cells that expressed DNS receptors but not control scFv receptors. Importantly, the 111In probe preferentially localized to DNS receptors but not control receptors on tumors in mice as assessed by gamma camera imaging. By 48 h after intravenous injection, the uptake of the probe in tumors expressing DNS receptors was 72 times greater than the amount of probe in the blood. This targeting strategy may allow noninvasive assessment of the location, extent and persistence of gene expression in living animals and in the clinic.

Functional approach to treatment of back pain in primary care: a preliminary report.

BACKGROUND: Back pain is one of the most common problems encountered in primary care clinics and causes great loss of work time, economy and expenditure of medical care. Knowledge of the cause of low back pain and effective treatment are rudimentary. We studied the functional approach to treatment of back pain of two acute (M:F = 1:1) and thirty chronic (M:F = 12:18) patients with back pain seen at a rural primary care clinic in September and October 1992. METHODS: Patients were included after completing an agreement form regarding the treatment plan (emphasizing therapeutic exercise, health education and as little medication as possible) in the first interview. A primary care physician specialised in family medicine personally gave treatment to the patients with free attendance to the clinic. A functional approach was adopted in four categories-therapeutic exercise, static and dynamic body biomechanics, awareness of proprioception, and maintenance of relaxed and balanced muscle tone. The patients were encouraged to perform daily activities rather than rest. RESULTS: Two patients with acute back pain gained complete relief without medication, modalities, equipment or other treatment one and two weeks after the first visit, respectively. Among the 30 chronic patients, after eight weeks of treatment, 12/30 (40%) gained complete relief from pain, 4/30 (13.3%) obtained more than 3/4 and less than complete relief, 7/30 (23.3%) had more than 1/2 and less than 3/4 relief, 2/30 (6.7%) gained less than 1/2 pain relief, 1/30 (3.3%) had no improvement, 1/30 (3.3%) deteriorated, and 3/30 (10%) were lost during surveillance. The patients reported no loss of work time attributed to back pain. Two acute patients visited the clinic four times and three times, respectively. The former received three prescriptions for an upper respiratory infection one month after complete remission of back pain, and the latter received no prescriptions for medication. On average, each chronic patient visited the clinic 4.83 times in 8 weeks. In only 25 of 145 (17.2%) visits was medication prescribed for other indications, and in 8 of 145 (5.5%) visits vitamin B complex or Alinamin-F for placebo was prescribed. We used neither modalities nor equipment. Only 7/30 (23.3%) patients received concurrent treatment from other medical institutions. Regarding compliance with the programmed exercise at home, two acute patients complied well. Among the 30 chronic patients, 22 (73.3%) had good compliance, 3 (10%) had poor compliance, 2 (6.7%) failed to comply and 3 (10%) were lost in follow up. CONCLUSIONS: Treating patients with back pain in primary care clinics with a functional approach by physicians appropriately trained in primary care was a good, efficacious, economic, and practical way, although neglected elsewhere. Further research and practice in our society might be worth while.