A New Method Used to Enhance the SPAIR Image of the Spine MRI.

BACKGROUND: Magnetic resonance imaging (MRI) is a handy diagnostic tool for orthopedic disorders, particularly spinal and joint diseases. METHODS: The lumbar intervertebral disc is visible in the T1 and T2 weight sequences of the spine MRI, which aids in diagnosing lumbar disc herniation, lumbar spine tuberculosis, lumbar spine tumors, and other conditions. The lumbar intervertebral disc cannot be seen accurately in the Spectral Attenuated Inversion Recovery (SPAIR) due to weaknesses in the fat and frequency offset parameters, which is not conducive to developing the intelligence diagnosis model of medical image. RESULTS: In order to solve this problem, we propose a composite framework, which is first to use the contrast limited adaptive histogram equalization (CLAHE) method to enhance the SPAIR image contrast of the spine MRI and then use the non-local means method to remove the noise of the image to ensure that the image contrast is uniform without losing details. We employ the Information Entropy (IE), Peak signal-to-noise ratio (PSNR), and feature similarity index measure (FSIM) to quantify image quality after enhancement by the composite framework. CONCLUSION: The outcomes of the experiments' output images and quantitative data indicate that our composite framework is better than others.

Mobile schwannoma of the lumbar spine: A case report and literature review.

BACKGROUND: Schwannoma is a benign tumor that originates from the cells of nerve sheaths. The occurrence of mobile schwannoma of the lumbar spine is extremely rare, and when clinicians perform spinal explorations in the expected locations, the results are often negative. This report presents a case of mobile schwannoma in the lumbar spine, aiming to remind doctors to consider the possibility of tumor migration during preoperative planning, thereby avoiding secondary harm to the patient. CASE REPORT: A 48-year-old male patient presented with a 2-year history of lower back pain and numbness in both lower extremities, which has progressively worsened over the past 3 months. An Magnetic resonance imaging scan revealed an oval-shaped lesion located in the L2/3 vertebral segment, which migrated to the L3/4 vertebral segment following contrast enhancement. The patient underwent tumor resection surgery, and the diagnosis of schwannoma was confirmed through pathological examination. CONCLUSION: Clinical physicians should increase their understanding of mobile schwannoma of the lumbar spine and utilize imaging techniques to accurately locate the tumor before surgery, in order to avoid unnecessary surgical scope and the risks of additional surgery.

Molecular Mechanism of Gelsemium elegans (Gardner and Champ.) Benth. Against Neuropathic Pain Based on Network Pharmacology and Experimental Evidence.

Gelsemium elegans (Gardner and Champ.) Benth. (Gelsemiaceae) (GEB) is a toxic plant indigenous to Southeast Asia especially China, and has long been used as Chinese folk medicine for the treatment of various types of pain, including neuropathic pain (NPP). Nevertheless, limited data are available on the understanding of the interactions between ingredients-targets-pathways. The present study integrated network pharmacology and experimental evidence to decipher molecular mechanisms of GEB against NPP. The candidate ingredients of GEB were collected from the published literature and online databases. Potentially active targets of GEB were predicted using the SwissTargetPrediction database. NPP-associated targets were retrieved from GeneCards, Therapeutic Target database, and DrugBank. Then the protein-protein interaction network was constructed. The DAVID database was applied to Gene Ontology and Kyoto Encyclopedia of Genes and Genome pathway enrichment analysis. Molecular docking was employed to validate the interaction between ingredients and targets. Subsequently, a 50 ns molecular dynamics simulation was performed to analyze the conformational stability of the protein-ligand complex. Furthermore, the potential anti-NPP mechanisms of GEB were evaluated in the rat chronic constriction injury model. A total of 47 alkaloids and 52 core targets were successfully identified for GEB in the treatment of NPP. Functional enrichment analysis showed that GEB was mainly involved in phosphorylation reactions and nitric oxide synthesis processes. It also participated in 73 pathways in the pathogenesis of NPP, including the neuroactive ligand-receptor interaction signaling pathway, calcium signaling pathway, and MAPK signaling pathway. Interestingly, 11-Hydroxyrankinidin well matched the active pockets of crucial targets, such as EGFR, JAK1, and AKT1. The 11-hydroxyrankinidin-EGFR complex was stable throughout the entire molecular dynamics simulation. Besides, the expression of EGFR and JAK1 could be regulated by koumine to achieve the anti-NPP action. These findings revealed the complex network relationship of GEB in the "multi-ingredient, multi-target, multi-pathway" mode, and explained the synergistic regulatory effect of each complex ingredient of GEB based on the holistic view of traditional Chinese medicine. The present study would provide a scientific approach and strategy for further studies of GEB in the treatment of NPP in the future.

Association between vein diameters, reflux characteristics, and clinical severity in patients with chronic venous insufficiency in Northwest China.

OBJECTIVE: Our goal was to summarize the relationship between vein diameters, reflux characteristics, and clinical severity in consecutive patients with chronic venous insufficiency (CVI) in Northwest China. METHODS: We evaluated 531 consecutive patients with CVI (249 women) who presented to the Department of Ultrasound of Xijing Hospital from September 2017 to July 2019. Reflux times and the mean diameters of the great saphenous, the small saphenous, and the calf perforator veins based on duplex ultrasound scans obtained in the standing position were recorded. Venous-specific assessment tools-the Heaviness, Achiness, Swelling, Throbbing, Itching (HASTI) score, the Venous Clinical Severity Score (VCSS), and the Clinical, Etiological, Anatomical, Pathophysiological (CEAP) class-were analyzed. Regression analysis was used to investigate the relationship between the clinical scores, vein diameters, and reflux times. A P value of less than .05 was considered statistically significant. RESULTS: We analyzed 531 consecutive patients with 728 limbs. The mean age was 55.24 ± 11.38 years; the mean body mass index (BMI) was 24.75 ± 3.49 kg/m2. Three hundred thirty-four patients (62.9%) presented with unilateral limb findings and 197 (37.1%), with bilateral limb involvement. No significant changes were noted in age and BMI across CEAP classes (F = 2.322 and F = 3.917, respectively; P > .05 for both). Both the HASTI score (r2 = 0.8741; P < .001) and the VCSS (r2 = 0.9257; P < .001) correlated with the CEAP class. The HASTI score strongly correlated with the mean diameters of the great saphenous and small saphenous veins (r2 = 0.9252, r2 = 0.6304, respectively; P < .001 for both) similarly to VCSS (r2 = 0.9396, r2 = 0.7195, respectively; P < .001 for both). The HASTI score and VCSS correlated equally with the mean diameters of the calf perforator veins (r = 0.7773 and r = 0.7781, respectively; P < .001 for both). In those with C6, both great saphenous vein (F = 4.608; P < .001) and small saphenous vein reflux times (F = 14.97; P < .001) were significantly higher than those in C1. Both the HASTI score and VCSS strongly associated with the reflux times of the great saphenous (r2 = 0.7706 and r2 = 0.8181, respectively; P < .001 for both) and small saphenous veins (r2 = 0.6470 and r2 = 0.7865, respectively; P < .001 for both). CONCLUSIONS: This analysis is one of the few epidemiologic studies of patients with CVI in Northwest China. Age and BMI did not correlate with CEAP class. Both the HASTI score and VCSS correlated strongly with the CEAP classification; vein diameters and reflux time in both the great saphenous vein and the small saphenous vein, indicating the validity of these outcome tools to venous hemodynamics and to CVI in general.

Systemic Endothelial Activation Is Associated With Early Acute Respiratory Distress Syndrome in Children With Extrapulmonary Sepsis.

OBJECTIVES: Systemic endothelial activation may contribute to sepsis-associated organ injury, including acute respiratory distress syndrome. We hypothesized that children with extrapulmonary sepsis with versus without acute respiratory distress syndrome would have plasma biomarkers indicative of increased endothelial activation and that persistent biomarker changes would be associated with poor outcome. DESIGN: Observational cohort. SETTING: Academic PICU. PATIENTS: Patients less than 18 years old with sepsis from extrapulmonary infection with (n = 46) or without (n = 54) acute respiratory distress syndrome and noninfected controls (n = 19). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Endothelial (angiopoietin-1, angiopoietin-2, tyrosine kinase with immunoglobulin-like loop epidermal growth factor homology domain 2, vascular endothelial growth factor, soluble fms-like tyrosine kinase, von Willebrand factor, E-selectin, intercellular adhesion molecule, vascular cell adhesion molecule, thrombomodulin) and inflammatory biomarkers (C-reactive protein, interleukin-6, and interleukin-8) were measured from peripheral plasma collected within 3 days (time 1) of sepsis recognition and at 3-6 days (time 2) and 7-14 days (time 3). Time 1 biomarkers and longitudinal measurements were compared for sepsis patients with versus without acute respiratory distress syndrome and in relation to complicated course, defined as greater than or equal to two organ dysfunctions at day 7 or death by day 28. Angiopoietin-2, angiopoietin-2/angiopoietin-1 ratio, tyrosine kinase with immunoglobulin-like loop epidermal growth factor homology domain 2, vascular endothelial growth factor, von Willebrand factor, E-selectin, intercellular adhesion molecule, vascular cell adhesion molecule, thrombomodulin, endocan, C-reactive protein, interleukin-6, and interleukin-8 were different between sepsis and noninfected control patients at time 1. Among patients with sepsis, those with acute respiratory distress syndrome had higher angiopoietin-2/angiopoietin-1 ratio, vascular endothelial growth factor, vascular cell adhesion molecule, thrombomodulin, endocan, interleukin-6, and interleukin-8 than those without acute respiratory distress syndrome (all p < 0.003). Angiopoietin-2 and angiopoietin-2/angiopoietin-1 ratio remained higher in sepsis with versus without acute respiratory distress syndrome after multivariable analyses. Time 1 measures of angiopoietin-2, angiopoietin-2/-1 ratio, von Willebrand factor, and endocan were indicative of complicated course in all sepsis patients (all area under the receiver operating curve ≥ 0.80). In sepsis without acute respiratory distress syndrome, soluble fms-like tyrosine kinase decreased more quickly and von Willebrand factor and thrombomodulin decreased more slowly in those with complicated course. CONCLUSIONS: Children with extrapulmonary sepsis with acute respiratory distress syndrome had plasma biomarkers indicative of greater systemic endothelial activation than those without acute respiratory distress syndrome. Several endothelial biomarkers measured near sepsis recognition were associated with complicated course, whereas longitudinal biomarker changes yielded prognostic information only in those without sepsis-associated acute respiratory distress syndrome.

Acetyl-11-keto-ß-boswellic acid regulates the repair of rat sciatic nerve injury by promoting the proliferation of Schwann cells.

AIMS: This study aimed to study the effects of acetyl-11-keto-ß-boswellic acid (AKBA) on the regeneration of injured peripheral nerves and the ability of the extracellular signal-regulated kinase (ERK) signaling pathway to regulate the proliferation of Schwann cells and the formation of myelin. MAIN METHODS: A sciatic nerve crush injury model rats were randomly divided into the model control, low-, medium-, and high-dose AKBA groups. The repair of myelin damage was observed through Luxol Fast Blue staining and the expression of neurofilament-200 (NF200) protein was detected through immunohistochemical tests. The relative expression levels of ERK, Phosphorylated-ERK (p-ERK), c-Jun N-terminal Kinase (JNK), and Phosphorylated-JNK (p-JNK) proteins were detected in vitro in Schwann cells treated with AKBA. The effect of AKBA on P0 and P75 protein expression in Schwann cells was detected through siRNA-mediated ERK gene knockout. KEY FINDINGS: AKBA promotes the repair of rat sciatic nerve injury by elevating the phosphorylation of the ERK signaling pathway and by regulating the proliferation and myelination of Schwann cells. SIGNIFICANCE: This test can provide data support for AKBA to repair sciatic nerve injury, provide a theoretical basis for further revealing AKBA repair mechanism, and provide reference for clinical development of sciatic nerve injury drugs.

Acetyl-11-keto-ß-boswellic acid extracted from Boswellia serrata promotes Schwann cell proliferation and sciatic nerve function recovery.

Frankincense can promote blood circulation. Acetyl-11-keto-ß-boswellic acid (AKBA) is a small molecule with anti-inflammatory properties that is derived from Boswellia serrata. Here, we hypothesized that it may promote regeneration of injured sciatic nerve. To address this hypothesis, we established a rat model of sciatic nerve injury using a nerve clamping method. Rats were administered AKBA once every 2 days at doses of 1.5, 3, and 6 mg/kg by intraperitoneal injection for 30 days from the 1st day after injury. Sciatic nerve function was evaluated using the sciatic functional index. Degree of muscle atrophy was measured using the triceps surae muscle Cuadros index. Neuropathological changes were observed by hematoxylin-eosin staining. Western blot analysis was used to detect expression of phospho-extracellular signal-regulated kinase 1 and 2 (p-ERK1/2) in injured nerve. S100 immunoreactivity in injured nerve was detected by immunohistochemistry. In vivo experiments showed that 3 and 6 mg/kg AKBA significantly increased sciatic nerve index, Cuadros index of triceps muscle, p-ERK1/2 expression, and S100 immunoreactivity in injured sciatic nerve of sciatic nerve injury model rats. Furthermore, for in vitro experiments, Schwann cells were treated with AKBA at 0-20 µg/mL. Proliferation of Schwann cells was detected by Cell Counting Kit-8 colorimetry assay. The results showed that 2 µg/mL AKBA is the optimal therapeutic concentration. In addition, ERK phosphorylation levels increased following 2 µg/mL AKBA treatment. In the presence of the ERK1/2 inhibitor, PD98059 (2.5 µL/mL), the AKBA-induced increase in p-ERK1/2 protein expression was partially abrogated. In conclusion, our study shows that AKBA promotes peripheral nerve regeneration with ERK protein phosphorylation playing a key role in this process.

Dracorhodin perchlorate regulates fibroblast proliferation to promote rat's wound healing.

In recent years, plant-derived extracts are increasing interest from researchers worldwide due to good efficacy and lower side effects. Among the different plant extracts, Dracorhodin perchlorate (DP) is originated from Dragon's blood which has long been used as a natural medicine with various pharmacological activities. In the present study, we have explored the potential regulation of DP on fibroblast proliferation which promotes wound healing both in vitro and in vivo. DP at treatment of 12-24 h significantly induced fibroblast proliferation which is associated with increasing level of phosphorylated-extracellular signal-regulated kinase (ERK). Moreover, if ERK is halted with siRNA, DP cannot induce fibroblast proliferation. In vivo, DP ointment treatment at low- (2.5 µg/mL), medium- (5 µg/mL) and high-(10 µg/mL) doses, rat wounds healed more rapidly compared with the control group. After DP treatment for 7 days, Serpin family H member 1 (SERPINH1) staining confirmed enhanced fibroblast proliferation in the wound tissue. Finally, phosphorylated-ERK in the wound tissue remarkably increased with DP ointment treatment. Therefore, DP may be developed into a potential lead compounds for the treatment of wounds in clinical trials in the near future.

Effects of Angelica Extract on Schwann Cell Proliferation and Expressions of Related Proteins.

The present study investigated the effects of Angelica extract (AE) on Schwann cell proliferation and expressions of related proteins, including brain derived neurotrophic factor (BDNF), neural cell adhesion molecule (NCAM), and proliferating cell nuclear antigen (PCNA). Proliferation activity and cell cycles of SCs were evaluated by MTT assay and flow cytometry methods, respectively, after 12 h treatment of AE at different concentrations (62.5, 125, 250, 1000, 2000, 4000, and 8000 mg/L). SCs were treated by 500, 1000, and 2000 mg/L AE for 24 h or 48 h; the related genes mRNA and proteins expressions in SCs were detected by quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA) kit. At the concentration range of 125-2000 mg/L, the SC proliferation was induced by AE in a dose-dependent manner, especially 1000 and 2000 mg/L; cells in drug-treated groups showed the most increase. Cells counts were ascended significantly in (G2/M + S) phase compared to control group. BDNF, NCAM, and PCNA protein expressions significantly increased at drug-treated groups. Relative genes mRNA expressions levels were also significantly higher compared to control group. The results indicated that AE facilitated SC proliferation and related genes and proteins expressions, which provided a basic guideline for nerve injury repair in clinic.

The effects of rotenone-induced toxicity via the NF-κB-iNOS pathway in rat liver.

Rotenone has been used as a pesticide for many years, it is an environmental poison reported to cause neurological diseases. However, the effects of rotenone on the rat liver are unclear, as are the mechanisms of toxicity. In the present study, Sprague-Dawley (SD) rats were divided into five groups: control, dimethyl sulfoxide (DMSO), rotenone low-dose (1 mg/kg), rotenone mid-dose (2 mg/kg) and rotenone high-dose (4 mg/kg). The treatments were orally administered daily for 28 days, we assessed health status, mRNA expression levels of inflammatory factors, protein levels, nitric oxide (NO) content and histological changes. The results showed that body weight was significantly decreased in each rotenone group in a dose-dependent manner, compared with the control group. Rotenone significantly increased the mRNA levels of cyclooxygenase-2 (COX-2), nuclear factor kappaB (NF-κB), prostaglandin E2 (PGE2), inducible nitric oxide synthase (iNOS) and tumor necrosis factor (TNF-α) in each rotenone group compared with the control group, except iNOS and TNF-α mRNA expression in the low-dose group. The protein levels of COX-2 were significantly higher in each rotenone group compared with the control group, NF-κB protein expression were significantly higher in the rotenone mid and high-dose groups, but not in the low-dose group, compared with the control group, similar changes were observed in NO content. Additionally, histological analysis revealed that the most severe tissue damage occurred in the high-dose group. These results indicated that rotenone has toxic effect in rat liver relating to inflammatory factors. Our findings provide insight into the mechanisms of rotenone hepatotoxicity.

Dracorhodin Perchlorate Accelerates Cutaneous Wound Healing in Wistar Rats.

Dracorhodin perchlorate (DP) is extracted from Dragon's blood, which is widely used in traditional Chinese medicine, especially in wound healing. The aim of this paper is to investigate the influence of DP ointment, which contained DP dissolved in DMSO and mixed with Vaseline, on cutaneous wound healing in Wistar rats. Forty Wistar rats were divided into two groups: control and DP groups. The skin on the back of each rat was punched with two full-thickness wounds and then treated with the corresponding drug. After 3, 7, 10, 14, and 21 days, four rats were sacrificed for immunological, biochemical, and histological analyses. Compared with the control treatment, DP could significantly promote wound closure. Histological and biochemical analyses of the skin biopsies also showed that DP regulated the expression of inflammatory responses by TNF-α and IL-ß and by supporting wound tissue growth and collagen deposition. Western blot revealed that DP could also facilitate the expression of EGF and VEGF proteins. In conclusion, DP promotes wound healing.

Effect of Frankincense Extract on Nerve Recovery in the Rat Sciatic Nerve Damage Model.

This study investigated the effect of frankincense extract on peripheral nerve regeneration in a crush injury rat model. Forty-eight Sprague-Dawley rats were randomly divided into four groups: control and frankincense extract low-, medium-, and high-dose groups. At days 7, 14, 21, and 28 following the surgery, nerve regeneration and functional recovery were evaluated using the sciatic functional index (SFI), expression of GAP-43, and the proliferation of Schwann cells (SCs) in vivo and in vitro. At day 7, the SFI in the frankincense extract high-dose group was significantly improved compared with the control group. After day 14, SFI was significantly improved in the medium- and high-dose groups. There was no significant difference in GAP-43 expression among the groups at day 7. However, after day 14, expression of GAP-43 in the high-dose group was higher than that in the control group. Histological evaluation showed that the injured nerve of frankincense extract high-dose group recovered better than the other groups 28 days after surgery. Further, S100 immunohistochemical staining, MTT colorimetry, and flow cytometry assays all showed that frankincense extract could promote the proliferation of SCs. In conclusion, frankincense extract is able to promote sciatic nerve regeneration and improve the function of a crushed sciatic nerve. This study provides a new direction for the repair of peripheral nerve injury.

Monitoring bone marrow stem cells with a reporter gene system in experimental middle cerebral artery occlusion rat models.

UNLABELLED: This study was designed to investigate the feasibility of imaging bone marrow stem cells (BMSCs) in experimental middle cerebral artery occlusion (MCAO) rat models with a reporter gene-probe system, HSV1-tk-(131)I-2'-fluoro-2'-deoxy-1-ß-d-arabinofuranosyl-5-iodouracil ((131)I-FIAU), and to choose the best strategies for stem cell injection, image acquisition, and imaging in vivo. METHODS: A recombinant adenovirus (Ad5-TIBE) carrying the herpes simplex virus type 1 thymidine kinase (TK) reporter gene (HSV1-tk) linked via the internal ribosome entry site to the brain-derived neurotrophic factor therapeutic gene was prepared. After transfection with Ad5-TIBE, BMSCs were introduced into MCAO rat models via local injection into the brain or via injection into the lateral ventricle, carotid artery, and tail vein. Normal rats were used as controls. Twenty-four hours after (131)I-FIAU injection, rats were sacrificed for biodistribution analysis. The expression of the TK gene was evaluated by real-time quantitative polymerase chain reaction and Western blot analysis. Autoradiography was used for ex vivo imaging. SPECT images were obtained in MCAO rat models. RESULTS: The percentage injected dose per gram (%ID/g) in infarcted brain tissue in rats receiving the injection into the brain was 0.124 ± 0.013; this value was significantly higher than those in rats receiving the injection into the ventricle (0.052 ± 0.004), carotid artery (0.061 ± 0.002), and tail vein (0.059 ± 0.005) as well as normal rats (0.005 ± 0.001). No differences were seen in the other cell transplantation groups. The %ID/g in infarcted brain tissue was higher than that in the contralateral brain tissue in all experimental rats but not in normal rats. The expression of the TK gene in rats receiving a local injection into the brain was superior to that in all of the other groups. TK messenger RNA and protein expression showed a positive correlation with the %ID/g in brain tissue. Greater radioactivity at the injection site than in the surrounding and contralateral brain tissues in all experimental rats was indicated through autoradiography. The ratio of counts in bilateral brain tissues reached its peak (6.63) 24 h after (131)I-FIAU injection. SPECT images showed that radioactivity accumulation in the brain was low but increased gradually over time. CONCLUSION: The HSV1-tk-(131)I-FIAU reporter gene-probe system may be used to monitor BMSC activity in experimental MCAO rat models. Local injection of stem cells may provide an optimal means for cell transplantation, and imaging with (131)I-FIAU 24 h after injection provides peak target-to-nontarget count ratios.

Autoradiography study and SPECT imaging of reporter gene HSV1-tk expression in heart.

AIM: To demonstrate the feasibility and optimal conditions of imaging herpes simplex virus 1-thymidine kinase (HSV1-tk) gene transferred into hearts with (131)I-2'-fluoro-2'-deoxy-1-beta-D-arabinofuranosyl-5-iodouracil ((131)I-FIAU) using autoradiography (ARG) and single photon emission computed tomography (SPECT) in animal models. METHODS: HSV1-tk inserted into adenovirus vector (Ad5-tk) and adenovirus (Ad5-null) was prepared. Rats or rabbits were divided into a study group receiving intramyocardial injection of Ad5-tk, and a control group receiving Ad-null injection. In the study group of rats, two sets of experiments, time-course study and dose-dependence study, were performed. In time-course experiments, rats were injected with (131)I-FIAU on Days 1, 2, 3, 5 and 7, after transfection of 1x10(8) pfu Ad5-tk, to study the feasibility and suitable time course for reporter gene imaging. In dose-dependence study, various titers of Ad5-tk (5x10(8), 1x10(8), 5x10(7) and 1x10(7) pfu) were used to determine the threshold and optimal viral titer needed for detection of gene expression. The gamma counts of hearts were measured. The rat myocardium was analyzed by ARG and reverse transcriptase-polymerase chain reaction (RT-PCR). SPECT whole-body planar imaging and cardiac tomographic imaging were performed in the rabbit models. RESULTS: From the ARG images, rats injected with Ad5-tk showed significant (131)I-FIAU activity in the anterolateral wall compared with background signals seen in the control Ad5-null rats. In time-course study, the highest radioactivity in the focal myocardium could be seen on Day 1, and then progressively declined with time. In dose-dependence study, the level of (131)I-FIAU accumulation in the transfected myocardium declined with the decrease of Ad viral titers. From the ARG analysis and gamma counting, the threshold viral titer was 5x10(7) pfu, and the optimal Ad titer was 1x10(8) pfu. The ARG images in region of interest-derived semi-quantitative study correlated well with ex vivo gamma counting and mRNA levels from RT-PCR analysis. The gamma counting and RT-PCR also correlated well with each other in both sets of experiments. Both SPECT planar and tomographic images showed clear uptake of (131)I-FIAU in the anterolateral wall where Ad5-tk was injected. CONCLUSION: The study confirmed the feasibility of cardiac SPECT reporter gene imaging with HSV1-tk as a reporter gene and (131)I-FIAU as a reporter probe. The optimal Ad5-tk titer for imaging was 1x10(8) pfu and the optimal imaging time was 1-2 days after gene transfer. Thus, the imaging of HSV1-tk transgene expression in the heart is feasible and may be used for the noninvasive SPECT imaging of gene therapy in cardiac diseases.