Factors secreted from dental pulp stem cells show multifaceted benefits for treating experimental temporomandibular joint osteoarthritis.

OBJECTIVE: Temporomandibular joint osteoarthritis (TMJOA) is a degenerative disease characterized by progressive cartilage degeneration, abnormal bone remodeling, and chronic pain. In this study, we aimed to investigate effective therapies to reverse or suppress TMJOA progression. DESIGN: To this end, we performed intravenous administration of serum free conditioned media from human exfoliated deciduous teeth stem cells (SHED-CM) into a mechanical-stress induced murine TMJOA model. RESULTS: SHED-CM administration markedly suppressed temporal muscle inflammation, and improved bone integrity and surface smoothness of the destroyed condylar cartilage. Moreover, SHED-CM treatment decreased the number of IL-1ß, iNOS, and MMP-13 expressing chondrocytes, whereas it specifically increased PCNA-positive cells in the multipotent polymorphic cell layer. Notably, the numbers of TdT-mediated dUTP nick end labeling (TUNEL)-positive apoptotic chondrocytes in the SHED-CM treated condyles were significantly lower than in those treated with DMEM, whereas the proteoglycan positive area was restored to a level similar to that of the sham treated group, demonstrating that SHED-CM treatment regenerated the mechanical-stress injured condylar cartilage and subchondral bone. Secretome analysis revealed that SHED-CM contained multiple therapeutic factors that act in osteochondral regeneration. CONCLUSIONS: Our data demonstrated that SHED-CM treatment promoted the regeneration and repair of mechanical-stress induced mouse TMJOA. Our observations suggest that SHED-CM has potential to be a potent tissue-regenerating therapeutic agent for patients with severe TMJOA.

eNOS plays an important role in the regulation of colonic inflammation: a novel therapeutic target and a predictive marker for the prognosis of ulcerative colitis.

BACKGROUND: We reported that deficiency of the eNOS protein exacerbates colitis induced by dextran sodium sulfate (DSS-induced colitis). However, the role of eNOS in colitis remains controversial. Therefore, we studied how over-expression of eNOS affected this inflammatory condition, using vascular endothelial cells and mice as in vitro and in vivo models, respectively. Furthermore, we investigated the influence of a polymorphism in the eNOS gene on the clinical features of ulcerative colitis (UC). METHODS: We examined the effect of eNOS overexpression on the expression of adhesion molecules in the endothelium and assessed the degree of DSS-induced colitis in eNOS transgenic (eNOS-Tg) mice. We also investigated the relationship between a polymorphism in the eNOS gene and clinical features of patients with UC. RESULTS: The expression of adhesion molecules, under inflammatory conditions, was attenuated in eNOS gene-transfected vascular endothelial cells, as measured by western blot analysis. Symptoms of DSS-induced colitis were likewise attenuated in eNOS-Tg mice, which exhibited lower weight loss, mortality, histological damage (by inflammation score and crypt damage score), and colonic myeloperoxidase activity, tumor necrosis factor-α expression, and MAdCAM-1 expression than in wild-type mice. Furthermore, there was a significant relationship between intractable cases of UC and a polymorphism in the eNOS gene promoter (c.-786 T > C) that decreases eNOS expression. CONCLUSION: The eNOS gene plays an important role in the regulation of colonic inflammation. The level of eNOS expression may be a predictive marker for prognosis of UC, and eNOS expression may be a novel therapeutic target.

KRAS mutations in primary tumours and post-FOLFOX metastatic lesions in cases of colorectal cancer.

BACKGROUND: KRAS mutations are predictive markers for the efficacy of anti-EGFR antibody therapies in patients with metastatic colorectal cancer. Although the mutational status of KRAS is reportedly highly concordant between primary and metastatic lesions, it is not yet clear whether genotoxic chemotherapies might induce additional mutations. METHODS: A total of 63 lesions (23 baseline primary, 18 metastatic and 24 post-treatment metastatic) from 21 patients who were treated with FOLFOX as adjuvant therapy for stage III/IV colorectal cancer following curative resection were examined. The DNA samples were obtained from formalin-fixed paraffin-embedded specimens, and KRAS, NRAS, BRAF and PIK3CA mutations were evaluated. RESULTS: The numbers of primary lesions with wild-type and mutant KRAS codons 12 and 13 were 8 and 13, respectively. The mutational status of KRAS remained concordant between the primary tumours and the post-FOLFOX metastatic lesions, irrespective of patient background, treatment duration and disease-free survival. Furthermore, the mutational statuses of the other genes evaluated were also concordant between the primary and metastatic lesions. CONCLUSION: Because the mutational statuses of predictive biomarker genes were not altered by FOLFOX therapy, specimens from both primary tumours and post-FOLFOX tumour metastases might serve as valid sources of DNA for known genomic biomarker testing.

Effects of transglucosidase on diabetes, cardiovascular risk factors and hepatic biomarkers in patients with type 2 diabetes: a 12-week, randomized, double-blind, placebo-controlled trial.

In this 12-week, randomized, double-blind, placebo-controlled trial, the efficacy and safety of transglucosidase (TGD) were compared with placebo in patients with type 2 diabetes mellitus (T2DM). At 12 weeks, TGD 300 mg/day and TGD 900 mg/day significantly reduced HbA1c (0.18 and 0.21%) and insulin concentration (19.4 and 25.0 pmol/l), respectively, vs. placebo. TGD 300 mg/day and TGD 900 mg/day also significantly reduced low-density lipoprotein cholesterol (0.22 and 0.17 mmol/l, respectively). TGD 900 mg/day significantly reduced triglyceride by 0.24 mmol/l and diastolic blood pressure by 8 mmHg. Placebo was associated with a significant increase from baseline in body mass index, alanine aminotransferase and aspartate aminotransferase (0.17 kg/m(2) , 3 and 2 U/l, respectively), whereas TGD was not. TGD 300 mg/day significantly increased high-molecular-weight adiponectin by 0.6 µg/ml. Adverse events did not differ significantly between the groups. TGD resulted in lowering of HbA1c and blood insulin level and improvements in metabolic and cardiovascular risk factors in T2DM.

KRAS mutations detected by the amplification refractory mutation system-Scorpion assays strongly correlate with therapeutic effect of cetuximab.

BACKGROUND: We aimed to compare the sensitive and quality-controlled KRAS testing with direct sequencing and to assess the impact on decision making of treatment. PATIENTS AND METHODS: We analysed genomic DNA isolated from macrodissected formalin-fixed paraffin-embedded specimens by direct sequencing and an amplification refractory mutation system-Scorpion assay (ARMS/S) method. Cetuximab was administered to patients identified as having wild-type (WT) KRAS using direct sequencing. Therapeutic effects were evaluated according to their KRAS status as determined by ARMS/S. RESULTS: Among the 159 patients, the overall mutation rate was determined to be 37.0% by direct sequencing and 44.0% by ARMS/S. For the patients diagnosed as WT by direct sequencing and treated with cetuximab (n=47), a response rate of 16.0% was observed for 38 ARMS/S WT patients, whereas 9 ARMS/S mutant (MUT) patients failed to respond. The ARMS/S WT patients showed significant improvement in progression-free survival (PFS) and overall survival (OS) compared with ARMS/S MUT patients (PFS median 5.0 vs 1.7 months, hazards ratio (HR)=0.29, P=0.001; OS median 12.1 vs 3.8 months, HR=0.26, P=0.001). CONCLUSION: Sensitive and quality-controlled KRAS testing may provide improved predictive power to determine the efficacy of anti-epidermal growth factor antibodies.

The effectiveness of packed therapy with three drugs in Helicobacter pylori eradication in Japan.

Primary Helicobacter pylori eradication rate using triple therapy (a proton pump inhibitor [PPI] + amoxicillin [AMPC] + clarithromycin [CAM], over 7 days) is showing a declining trend. In this study we report recent eradication rates and have evaluated the usefulness of a pack preparation of three drugs. H. pylori eradication rate was 85.1% (57/67) in 2004 but then fell to 75.2% (79/105) in 2005, 70.1% (68/97) in 2006 and 69.9% (58/83) in 2007. With the introduction of packs (lansoprazole [LPZ] 60 mg, AMPC 1500 mg, CAM 400 mg) the eradication rate recovered to 78.0% (110/141) in 2008. A comparative study in 2008 delineated that the eradication rate in the pack group (88.4%, 38/43) was significantly higher than that of the conventional group (73.5%, 72/98). These results suggest that packs of eradication medicine are useful in increasing eradication success.

BCL6 degradation caused by the interaction with the C-terminus of pro-HB-EGF induces cyclin D2 expression in gastric cancers.

BCL6 is a transcriptional repressor that has important functions in lymphocyte differentiation and lymphomagenesis, but there have been no reports of BCL6 expression in gastric cancers. In the present study, we investigated the BCL6 function in gastric cancers. Treatment with TPA resulted in BCL6 degradation and cyclin D2 upregulation. This phenomenon was inhibited by the suppression of the nuclear translocation of HB-EGF-CTF (C-terminal fragment of pro-HB-EGF). The HB-EGF-CTF nuclear translocation leads to the interaction of BCL6 with HB-EGF-CTF and the nuclear export of BCL6, and after that BCL6 degradation was mediated by ubiquitin/proteasome pathway. Real-time RT-PCR and siRNA targeting BCL6 revealed that BCL6 suppresses cyclin D2 expression. Our data indicate that BCL6 interacts with nuclear-translocated HB-EGF-CTF and that the nuclear export and degradation of BCL6 induces cyclin D2 upregulation. We performed immunohistochemical analyses of BCL6, HB-EGF and cyclin D2 in human gastric cancers. The inverse correlation between BCL6 and cyclin D2 was also found in HB-EGF-positive human gastric cancers. BCL6 degradation caused by the HB-EGF-CTF also might induce cyclin D2 expression in human gastric cancers. Inhibition of HB-EGF-CTF nuclear translocation and maintenance of BCL6 function are important for the regulation of gastric cancer progression.

RUNX3 expression correlates with chief cell differentiation in human gastric cancers.

RUNX3 is a novel tumor suppressor in gastric carcinogenesis and an important factor for differentiation of chief cells in the normal gastric fundic mucosa. In this study, we confirmed RUNX3 immunolocalization in the fundic gland (bottom part) but minimum in surface mucous cell epithelium (top part) in the isolated gland from fundic mucosa. We also analyzed RUNX3 expression by immunohistochemistry in 102 gastric cancers and made a histological assessment of the expression of differentiation markers to evaluate interrelations. Among them, 45 and 57 cases were judged to be RUNX3 positive and negative, respectively, and 33 and 69 cases were pepsinogen I positive and negative, with no link to histological types. RUNX3 expression was significantly associated with that of pepsinogen I (P<0.001), but not mucins, including MUC5AC and MUC6, or the parietal or intestinal phenotypes. In conclusion, the present study showed, for the first time to our knowledge, a relation between RUNX3 and pepsinogen I expression in human gastric cancers. RUNX3 is strongly associated with chief cell phenotypic expression in human gastric cancers, as well as in normal gastric mucosa, and could be considered to play an important role in maintaining the chief cell phenotype.

Gastric and intestinal phenotypic correlation between exocrine and endocrine components in human stomach tumors.

We have previously suggested that an origin of a stomach cancer is from a progenitor cell specializing toward exocrine cell (Exo-cell) lineages. To clarify whether our hypothesis is correct or not, we analyzed the expression of Exo-cell and endocrine cell (End-cell) markers in a series of lesions for comparison. We evaluated chromogranin A (CgA) expression in 37 early and 73 advanced stomach cancers, in 30 stomach adenomas, in 8 carcinoid tumors, and in 4 endocrine cell carcinomas (ECCs) with assessment of gastric and/or intestinal (G/I) phenotypes in both Exo-cell and End-cell by immunohistochemistry. CgA expression was observed in 10.8% of the early and 16.4% of the advanced stomach cancers, respectively. The End-cell G/I phenotypes were in line with the Exo-cell counterparts in the CgA-positive stomach cancerous areas, and there was strong association between Cdx2 expression and the intestinal End-cell markers. All of the adenoma cases had the intestinal Exo-cell phenotypic expression, with the positive link between Exo-cell and End-cell G/I phenotypes. All stomach carcinoids had CgA expression but no expression of Exo-cell markers. In conclusion, most stomach cancers might develop from a progenitor cell specializing towards Exo-cell lineages, but some cases possessed both Exo-cell and End-cell markers with maturely differentiated phenotypes. In such cases, Exo-cell and End-cell phenotypes were found to correlate strongly, suggesting the possibility of histogenesis from "cancer stem cells".

Endoscopic submucosal dissection is useful and safe for intramucosal gastric neoplasms in the elderly.

BACKGROUND AND STUDY AIMS: Endoscopic submucosal dissection (ESD) has recently gained popularity for use against intramucosal gastric neoplasms in Japan, but few studies have examined whether ESD is feasible for elderly patients. This study aims are to evaluate the efficacy and safety of ESD according to age in consecutive elderly patients treated with ESD. PATIENTS AND METHODS: Subjects comprised 116 patients (90 men, 26 women) with 125 lesions treated using ESD from November 2002 to March 2006 at Nagoya City University Hospital and Iwata Municipal Hospital, Japan. Patients were categorized into: Group A, <65-years-old (n=34); Group B, > or =65-years-old but <75-years-old (n=41); and Group C, > or = 75-years-old (n=41). En bloc resection rate and treatment time were examined according to age, tumour size and location, and frequency of complications was examined according to age. RESULTS: Rate of concomitant disease was significantly higher in Group C than in the other groups. En bloc resection rates and median treatment times were 91.4% and 80 min in Group A, 91.1% and 97 min in Group B and 86.7% and 110 min in Group C, respectively. No significant differences were noted between groups, or for en bloc resection rate and treatment time according to tumour size and location, or between groups for frequency of complications. CONCLUSIONS: ESD for gastric neoplasms is effective and safe in elderly patients, and may be positively recommended to elderly patients with intramucosal gastric neoplasms.

Mutations and nuclear accumulation of beta-catenin correlate with intestinal phenotypic expression in human gastric cancer.

AIMS: Abnormal localization of beta-catenin is frequently observed in human gastric cancers. The aim of the present study was to evaluate relationships among gastrointestinal differentiation phenotypes, beta-catenin localization and mutations of Wnt signalling genes. METHODS AND RESULTS: Seventy-seven regions in 39 gastric adenocarcinomas were classified according to beta-catenin localization and gastric and intestinal phenotypes. Cases with membranous beta-catenin localization showed a gradual decrease from gastric (G) (55% = 6/11) and gastric-and-intestinal-mixed (GI) (17% = 5/29) to intestinal (I) (0% = 0/21) phenotypes, while those with nuclear localization showed a concomitant increase: 18% (2/11), 41% (12/29), 95% (20/21) and 63% (10/16) for G, GI, I and null type (N), respectively (P < 0.001, membranous versus nuclear localization in G, GI through I). Mutations in exon 3 of the beta-catenin gene were found in G (50% = 1/2), GI (67% = 8/12), I (45% = 9/20) and N (0% = 0/10) regions with nuclear beta-catenin localization (GI versus N, P < 0.01; I versus N, P < 0.05). Adenomatous polyposis coli (APC) gene mutations were demonstrated only in GI, I and N types, irrespective of beta-catenin localization. Molecular analysis of these genes revealed 10 tumours to be heterogeneous out of 16 informative cases (62.5%). CONCLUSION: Intestinal phenotypic expression is accompanied by a shift from membranous to cytoplasmic/nuclear accumulation of beta-catenin. In contrast, N-type regions may progress along a different pathway.

Functional dissection of YabA, a negative regulator of DNA replication initiation in Bacillus subtilis.

The regulation of initiation of DNA replication is crucial to ensure that the genome is replicated only once per cell cycle. In the Gram-positive bacterium Bacillus subtilis, the function of the YabA protein in initiation control was assigned based on its interaction with the DnaA initiator and the DnaN sliding clamp in the yeast two-hybrid and on the overinitiation phenotype observed in a yabA null strain. However, YabA is unrelated to known regulators of initiation and interacts with several additional proteins that could also be involved directly or not in initiation control. Here, we investigated the specific role of YabA interactions with DnaA and DnaN in initiation control by identifying single amino acid changes in YabA that disrupted solely the interaction with DnaA or DnaN. These disruptive mutations delineated specific interacting surfaces involving a Zn2+-cluster structure in YabA. In B. subtilis, these YabA interaction mutations abolished both initiation control and the formation of YabA foci at the replication factory. Upon coexpression of deficient YabA mutants, mixed oligomers formed foci at the replisome and restored initiation control, indicating that YabA acts within a heterocomplex with DnaA and DnaN. In agreement, purified YabA oligomerized and formed complexes with DnaA and DnaN. These findings underscore the functional association of YabA with the replication machinery, indicating that YabA regulates initiation through coupling with the elongation of replication.

Efficacy of famotidine and omeprazole in healing symptoms of non-erosive gastro-oesophageal reflux disease: randomized-controlled study of gastro-oesophageal reflux disease.

BACKGROUND: The epidemiology and pathophysiology of non-erosive gastro-oesophageal reflux disease differs from erosive gastro-oesophageal reflux disease. There is a possibility that non-erosive gastro-oesophageal reflux disease treatment requires a different regimen/approach but it is not yet acknowledged. AIM: To investigate the efficacy of famotidine and omeprazole in the treatment of gastro-oesophageal reflux disease, especially non-erosive gastro-oesophageal reflux disease. PATIENTS AND METHODS: A randomized, open-label trial was conducted. Fifty-four gastro-oesophageal reflux disease patients were assigned to treatment with famotidine at a dosage of 20 mg twice daily; or omeprazole, 20 mg once daily, for a period of 8 weeks. The Short Form-36 Health Survey and Gastrointestinal Symptom Rating Scale administered at baseline and after 8 weeks of treatment as well as a symptom questionnaire were conducted daily. RESULTS: Short Form-36 revealed that gastro-oesophageal reflux disease has severe impact on health-related quality of life. Thirty-nine subjects (77%) were endoscopically diagnosed as non-erosive gastro-oesophageal reflux disease. The mean Gastrointestinal Symptom Rating Scale abdominal pain, and indigestion score of non-erosive gastro-oesophageal reflux disease significantly improved in famotidine-treated patients (P < 0.05), but not in the omeprazole. There was no significant change regarding improved heartburn symptoms of non-erosive gastro-oesophageal reflux disease between treatments in the daytime or night-time. CONCLUSION: Famotidine and omeprazole were both effective in improving symptoms of gastro-oesophageal reflux disease, particularly non-erosive gastro-oesophageal reflux disease.

Functional analysis of a novel gene, DD3-3, from Dictyostelium discoideum.

A novel gene, DD3-3, from Dictyostelium discoideum has been isolated by an mRNA differential display between a wild-type strain AX2 and a mutant HG794 which is defective in O-glycosylation. Functional analysis of the novel gene, DD3-3, was conducted by preparing a knockout mutant, DD3-3KO, and a GST:DD3-3 fusion protein. The mutant DD3-3KO cells were allowed to develop about 1.5 h earlier than the wild-type strain AX2 cells. Northern blotting analysis of the knockout mutant cells showed a remarkable downregulation of Reg A, cAMP-dependent phosphodiesterase, and overexpression of protein tyrosine kinase (PTK) during early development and its shutdown during late development. The relationship between O-glycosylation and phosphorylation involving Reg A gene is discussed.

Bayesian joint prediction of associated transcription factors in Bacillus subtilis.

Sigma factors, often in conjunction with other transcription factors, regulate gene expression in prokaryotes at the transcriptional level. Specific transcription factors tend to co-occur with specific sigma factors. To predict new members of the transcription factor regulon, we applied Bayes rule to combine the Bayesian probability of sigma factor prediction calculated from microarray data and the sigma factor binding sequence motif, the motif score of the transcription factor associated with the sigma factor, the empirically determined distance between the transcription start site to the cis-regulatory region, and the tendency for specific sigma factors and transcription factors to co-occur. By combining these information sources, we improve the accuracy of predicting regulation by transcription factors, and also confirm the sigma factor prediction. We applied our proposed method to all genes in Bacillus subtilis to find currently unknown gene regulations by transcription factors and sigma factors.

Mutations in the hypoxanthine guanine phosphoribosyltransferase gene (HPRT1) in Asian HPRT deficient families.

Inherited mutation of hypoxanthine guanine phosphoribosyltransferase, (HPRT) gives rise to Lesch-Nyhan syndrome or HPRT-related gout. We have identified 34 mutations in 28 Japanese, 7 Korean, and 1 Indian families with the patients manifesting different clinical phenotypes, including two rare cases in female subjects, by the analysis of all nine exons of HPRT from the genomic DNA and reverse transcribed mRNA using PCR technique coupled with direct sequencing.

Predicting gene regulation by sigma factors in Bacillus subtilis from genome-wide data.

MOTIVATION: Sigma factors regulate the expression of genes in Bacillus subtilis at the transcriptional level. We assess the accuracy of a fold-change analysis, Bayesian networks, dynamic models and supervised learning based on coregulation in predicting gene regulation by sigma factors from gene expression data. To improve the prediction accuracy, we combine sequence information with expression data by adding their log-likelihood scores and by using a logistic regression model. We use the resulting score function to discover currently unknown gene regulations by sigma factors. RESULTS: The coregulation-based supervised learning method gave the most accurate prediction of sigma factors from expression data. We found that the logistic regression model effectively combines expression data with sequence information. In a genome-wide search, highly significant logistic regression scores were found for several genes whose transcriptional regulation is currently unknown. We provide the corresponding RNA polymerase binding sites to enable a straightforward experimental verification of these predictions.

Predicting the operon structure of Bacillus subtilis using operon length, intergene distance, and gene expression information.

We predict the operon structure of the Bacillus subtilis genome using the average operon length, the distance between genes in base pairs, and the similarity in gene expression measured in time course and gene disruptant experiments. By expressing the operon prediction for each method as a Bayesian probability, we are able to combine the four prediction methods into a Bayesian classifier in a statistically rigorous manner. The discriminant value for the Bayesian classifier can be chosen by considering the associated cost of misclassifying an operon or a non-operon gene pair. For equal costs, an overall accuracy of 88.7% was found in a leave-one-out analysis for the joint Bayesian classifier, whereas the individual information sources yielded accuracies of 58.1%, 83.1%, 77.3%, and 71.8% respectively. The predicted operon structure based on the joint Bayesian classifier is available from the DBTBS database (http://dbtbs.hgc.jp).

Localization of breast sentinel lymph nodes by MR lymphography with a conventional gadolinium contrast agent. Preliminary observations in dogs and humans.

PURPOSE: To test the capability of an indirect MR lymphography (MRLG) using a conventional extracellular gadolinium (Gd)-based contrast agent for localizing breast sentinel lymph node (SLN). METHODS: A total of 1 and 0.5 ml of undiluted gadopentetate dimeglumine were injected subcutaneously into the two periareolar areas overlying each caudal mammary gland in 10 female dogs. Contiguous 2-mm-thick fast gradient echo MR images were acquired through the upper breast and axilla before and for 60 min after gentle massage at the injection sites, yielding 3D displays. The localized SLN was resected from the living animals, followed by post mortem examinations. MRLG (1 ml contrast agent injected) was also attempted in 5 female volunteers. RESULTS: Even with 0.5-ml contrast agent, the MRLG clearly visualized the connection of SLN and lymphatic vessels directly draining from the injection sites, and the remaining distant nodes, with the maximal enhancement peaks within 10 min after massage. The 3D images provided comprehensive anatomy of these lymphatic pathways in each axilla. Of the 20 SLN and 128 distant nodes visualized on the MRLG, all the SLN (100%) and 107 (83.5%) distant nodes could be resected pre- and post mortem, in good correlation with the locations and sizes on the MR images. MRLG also effectively localized SLN in the volunteers, without significant adverse effects. CONCLUSION: An indirect MRLG using small volumes of conventional Gd-based contrast agent may have potential for accurate identification and surgical biopsy of breast SLN.

Assessment of regional lung ventilation in dog lungs with Gd-DTPA aerosol ventilation MR imaging.

PURPOSE: Gd-DTPA aerosol ventilation MR imaging was obtained using a modified aerosol delivery system with an aerosol reservoir to non-invasively assess regional lung ventilation in dogs. MATERIAL AND METHODS: Seven anesthetized, spontaneously breathing normal dogs inhaled 200 mmol Gd/l Gd-DTPA aerosol produced by an ultrasonic nebulizer, using an open-circuit aerosol delivery system with or without an aerosol reservoir. Fast gradient-echo MR images were sequentially acquired with an interval time of 1 min for 25 min before and after aerosol inhalation. The aerosol study was also performed using the aerosol delivery system with an aerosol reservoir in the same 7 dogs after airway obstruction with a balloon catheter, and in another 7 dogs after pulmonary arterial embolization with enbucrilate. An i.v. Gd-DTPA-enhanced dynamic MR study after i.v. bolus injection of a 0.1 mmol/kg dose of Gd-DTPA was combined to assess regional lung perfusion. Lung enhancement effect was evaluated by time-signal intensity curves and the subtracted ventilation- and perfusion-weighted images. RESULTS: With or without the aerosol reservoir, the normal dog lungs were gradually and gravity-dependently enhanced with time after aerosol inhalation. The use of the aerosol reservoir, however, showed significantly greater lung enhancement without a significant increase in breathing rate and with minimal reduction in PaO2 of less than 5 mm Hg in these animals. The enhancement effect of i.v. injection of Gd-DTPA at pulmonary arterial perfusion phase was significantly greater compared to that of Gd-DTPA aerosol throughout the normal lungs, and the subtracted ventilation-weighted and perfusion-weighted images showed homogeneous but gravity-dependent aerosol deposition and perfusion. These images clearly defined the regionally matched perfusion-ventilation deficits in the lung regions distal to bronchial obstruction in all the airway obstruction dogs, and the regionally mismatched perfusion-ventilation in the embolized regions of all the pulmonary arterial embolization animals. CONCLUSION: Gd-based aerosol can non-invasively image regional lung ventilation in spontaneously breathing animals, using an adequate aerosol delivery system. The combined use of Gd-DTPA perfusion MR imaging may be acceptable for defining regionally impaired lung function associated with acute airway obstruction and pulmonary arterial embolization.