Metal organic framework synthesis in the presence of surfactants: towards hierarchical MOFs?

The effect of synthesis pH and H2O/EtOH molar ratio on the textural properties of different aluminium trimesate metal organic frameworks (MOFs) prepared in the presence of the well-known cationic surfactant cetyltrimethylammonium bromide (CTAB) at 120 °C was studied with the purpose of obtaining a MOF with hierarchical pore structure. Depending on the pH and the solvent used, different topologies were obtained (namely, MIL-96, MIL-100 and MIL-110). On the one hand, MIL-110 was obtained at lower temperatures than those commonly reported in the literature and without additives to control the pH; on the other hand, MIL-100 with crystallite sizes as small as 30 ± 10 nm could be easily synthesized in a mixture of H2O and EtOH with a H2O/EtOH molar ratio of 3.4 at pH 2.6 in the presence of CTAB. The resulting material displays a hierarchical porosity that combines the microporosity from the MOF and the non-ordered mesopores defined in between the MOF nanoparticles. Interestingly, the maximum of the pore size distribution could be varied between 3 and 33 nm. Finally, at pH 2.5 and using water as a solvent, platelets of MIL-96, a morphology never observed before for this MOF, were synthesized with a (001) preferential crystal orientation, the (001) plane running parallel to the bipyramidal cages of the MIL-96 topology.

Aerosolised 5-azacytidine suppresses tumour growth and reprogrammes the epigenome in an orthotopic lung cancer model.

BACKGROUND: Epigenetic silencing by promoter methylation and chromatin remodelling affects hundreds of genes and is a causal event for lung cancer. Treatment of patients with low doses of the demethylating agent 5-azacytidine in combination with the histone deacetylase inhibitor entinostat has yielded clinical responses. The subcutaneous dosing route for consecutive days and reduced bioavailability of 5-azacytidine because of inactivation by cytidine deaminase may limit the expansion of epigenetic therapy into Phase III trials. To mitigate these barriers, an aerosol of 5-azacytidine was generated and characterised. METHODS: The effect of aerosol vs systemic delivery of 5-azacytidine on tumour burden and molecular response of engrafted lung tumours in the nude rat was compared. RESULTS: Pharmacokinetics revealed major improvement in the half-life of 5-azacytidine in lung tissue with aerosol delivery. Aerosolised 5-azacytidine significantly reduced lung tumour burden and induced global demethylation of the epigenome at one-third of the comparable effective systemic dose. High commonality for demethylation of genes was seen in tumours sampled throughout lung lobes and across treated animals receiving the aerosolised drug. CONCLUSION: Collectively, these findings show that aerosolised 5-azacytidine targets the lung, effectively reprogrammes the epigenome of tumours, and is a promising approach to combine with other drugs for treating lung cancer.

Do we need real-time MRI for diagnosis of temporomandibular joint disorders?

INTRODUCTION: Magnetic resonance imaging (MRI) has been approved as an appropriate radiological modality for temporomandibular joint (TMJ) diagnosis, whereas the results of international multicenter studies impressively show the limitations of static three-dimensional MRI. The state of the art for dynamic imaging of the TMJ in real-time are TrueFISP sequences in one sagittal plane. In order to support the diagnostics, a computer-assisted visualization procedure has been developed by the authors for both the static and dynamic MRI. METHODS: A number of validated sequences are available for the static 3D-MRI within the clinical routine. For dynamic MRI in real-time, True-FISP sequences in one sagittal plane with a slice thickness of 5-10 mm and 1.3 mm x 1.3 mm spatial resolution were applied. Both the dynamic and static MRI datasets are animated and visualized using the computer-assisted procedure. RESULTS: The computer-assisted procedure reliably supported the clinical diagnosis, especially the visibility of the articular disc was enhanced. On the basis of the static MRI, a 60-year-old patient was diagnosed with anterior disc displacement without reduction. In contrast, by the dynamic MRI, it was recognized how the articular disc was firstly somehow stretched and flattened before the mandibular condyle again glided under the disc, thus resulting in an anterior disc displacement with reduction. CONCLUSION: These results endorse the relevance of real-time diagnosis for the TMJ. The computer-assisted visualization has been approved as a reliable help for clinical diagnosis.

Prospective evaluation of risk of vertebral fractures using quantitative ultrasound measurements and bone mineral density in a population-based sample of postmenopausal women: results of the Basel Osteoporosis Study.

OBJECTIVE: Prospective studies have shown that quantitative ultrasound (QUS) techniques predict the risk of fracture of the proximal femur with similar standardised risk ratios to dual-energy x-ray absorptiometry (DXA). Few studies have investigated these devices for the prediction of vertebral fractures. The Basel Osteoporosis Study (BOS) is a population-based prospective study to assess the performance of QUS devices and DXA in predicting incident vertebral fractures. METHODS: 432 women aged 60-80 years were followed-up for 3 years. Incident vertebral fractures were assessed radiologically. Bone measurements using DXA (spine and hip) and QUS measurements (calcaneus and proximal phalanges) were performed. Measurements were assessed for their value in predicting incident vertebral fractures using logistic regression. RESULTS: QUS measurements at the calcaneus and DXA measurements discriminated between women with and without incident vertebral fracture, (20% height reduction). The relative risks (RRs) for vertebral fracture, adjusted for age, were 2.3 for the Stiffness Index (SI) and 2.8 for the Quantitative Ultrasound Index (QUI) at the calcaneus and 2.0 for bone mineral density at the lumbar spine. The predictive value (AUC (95% CI)) of QUS measurements at the calcaneus remained highly significant (0.70 for SI, 0.72 for the QUI, and 0.67 for DXA at the lumbar spine) even after adjustment for other confounding variables. CONCLUSIONS: QUS of the calcaneus and bone mineral density measurements were shown to be significant predictors of incident vertebral fracture. The RRs for QUS measurements at the calcaneus are of similar magnitude as for DXA measurements.

[Hydatid disease in the Department of Health #2 of the Valencian Community (Spain)]. / Casos de hidatidosis en el Departamento de Salud 2 de la Comunidad Valenciana.

Hydatidosis is one of the most important zoonotic parasitic diseases of Mediterranean and South American countries where they constitute a significant health problem. Its diagnosis is realized essentially by image techniques and its treatment continues being eminently surgical. During the period 2000-2005, we reviewed clinical records of diagnosed and treated cases of hydatidosis carried out at the Department of Health 2 of the Valencia Community, Spain. Thirty three cases were evaluated of which we describe demographic, radiological, clinical, analytic, therapeutical and evolutionary data. We discuss the peculiarities found in them: thirty two cases were of hepatic location, essentially right, 48.5% unique cysts, five casual finding, 88.87% were diagnosed by ultrasonographic technique and in 2/3 of the cases the serology was positive. In addition, 52.17% of the twenty three cases treated surgically cured without recurrence and a 15.15% recurred without subsequent healing. Studies will require long-term monitoring of patients evolution.

[Rare complication after Le Fort I osteotomy]. / Eine seltene Komplikation nach Le-Fort-I-Osteotomie.

Malfunctions of the eustachian tube after Le Fort I osteotomies are rare. A 22-year-old woman was treated by Le Fort I osteotomy for maxillary retrognathism. Postoperatively she developed recurrent tubal malfunction and middle ear effusions on the left side, with no improvement after adenotomy, tonsillectomy, and grommet insertion. In consecutive computed tomography and magnetic resonance imaging scans, a forward dislocation of the left pterygoid hamulus was demonstrated. In addition, damage to the tensor veli palatini muscle was evident. Both postoperative sequelae appear to be responsible for the unilateral tubal dysfunction.

Loss of AP-2alpha results in deregulation of E-cadherin and MMP-9 and an increase in tumorigenicity of colon cancer cells in vivo.

Activator protein-2 (AP-2) is a transcription factor that regulates proliferation and differentiation in mammalian cells and has been implicated in the acquisition of the metastatic phenotype in several types of cancer. Herein, we examine the role of AP-2alpha in colon cancer progression. We provide evidence for the lack of AP-2alpha expression in the late stages of colon cancer cells. Re-expression of the AP-2alpha gene in the AP-2alpha-negative SW480 colon cancer cells suppressed their tumorigenicity following orthotopic injection into the cecal wall of nude mice. The inhibition of tumor growth could be attributed to the increased expression of E-cadherin and decreased expression and activity of matrix-metalloproteinase-9 (MMP-9) in the transfected cells, as well as a substantial loss of their in vitro invasive properties. Conversely, targeting constitutive expression of AP-2alpha in AP-2-positive KM12C colon cancer cells with small interfering RNA resulted in an increase in their invasive potential, downregulation of E-cadherin and increased expression of MMP-9. In SW480 cells, re-expression of AP-2alpha resulted in a fourfold increase in the activity of E-cadherin promoter, and a 5-14-fold decrease in the activity of MMP-9 promoter, indicating transcriptional regulation of these genes by AP-2alpha. Chromatin immunoprecipitation assay showed that re-expressed AP-2alpha directly binds to the promoter of E-cadherin, where it has been previously reported to act as a transcriptional activator. Furthermore, chromatin immunoprecipitation assay revealed AP-2alpha binding to the MMP-9 promoter, which ensued by decreased binding of transcription factor Sp-1 and changes in the recruitment of transcription factors to a distal AP-1 element, thus, contributing to the overall downregulation of MMP-9 promoter activity. Collectively, our data provide evidence that AP-2alpha acts as a tumor suppressor gene in colon cancer..

A novel AKT3 mutation in melanoma tumours and cell lines.

Recently, a rare activating mutation of AKT1 (E17K) has been reported in breast, ovarian, and colorectal cancers. However, analogous activating mutations in AKT2 or AKT3 have not been identified in any cancer lineage. To determine the prevalence of AKT E17K mutations in melanoma, the most aggressive form of skin cancer, we analysed 137 human melanoma specimens and 65 human melanoma cell lines for the previously described activating mutation of AKT1, and for analogous mutations in AKT2 and AKT3. We identified a single AKT1 E17K mutation. Remarkably, a previously unidentified AKT3 E17K mutation was detected in two melanomas (from one patient) as well as two cell lines. The AKT3 E17K mutation results in activation of AKT when expressed in human melanoma cells. This represents the first report of AKT mutations in melanoma, and the initial identification of an AKT3 mutation in any human cancer lineage. We have also identified the first known human cell lines with naturally occurring AKT E17K mutations.

A comprehensive classification of mandibular fractures: a preliminary agreement validation study.

This study evaluates a comprehensive classification system for mandibular fractures based on imaging analysis. The AO/ASIF scheme, defining three fracture types (A, B, C), three groups within each type (e.g. A1, A2, A3) and three subgroups within each group (e.g. A1.1, A1.2, A1.3) with increasing severity from A1.1 (lowest) to C3.3 (highest) was used. The mandible is divided into two vertical units (I and V), two lateral horizontal units (II and IV) and one central unit (III) comprising the symphyseal and parasymphyseal region. Type A fractures are non-displaced, type B are displaced and type C are multifragmentary/defect injuries. Groups and subgroups are further defined in the classification system. Two classification sessions using semi-automatic software with 7 and 9 surgeons were performed to evaluate 100 fracture cases in the first session and 50 in the second. Inter-observer reliability and individual rater's accuracy were evaluated by kappa coefficient and latent class analysis, respectively. The analysis of inter-observer agreement for the detailed coding showed kappa coefficients around 0.50 with higher agreement among raters in the vertical units. This system allows standardization of documentation of mandibular fractures, although improvement in the definition of categories and their application is required.

[Evaluation of two immunochromatography kits for rapid diagnosis of rotavirus infections]. / Evaluación de dos equipos inmunocromatográficos comerciales para el diagnóstico rápido de la infección por rotavirus.

A prospective study was conducted to evaluate two immunochromatography (ICG) commercial kits for diagnosis of rotavirus infection, VIKIA Rota-Adeno (bioMérieux) and Simple Rota-Adeno (Operon). Reverse transcriptase and polymerase chain reaction (RT-PCR) with specific primers for the VP7 gene of group A rotavirus was used as the reference method. The sensitivity and specificity of the ICG tests compared with those of the reference method were 98.4% and 84.8%, respectively, for Simple Rota-Adeno (Operon), and 100% and 24.2% for VlKIA Rota-Adeno (bioMérieux). It is remarkable the low specificity of the latter method, which yields a high number of false positive results. The predictive value of a positive result by this method was only 71.6%. Most of the detected rotavirus strains corresponded to genotype G9P[8] (65%), followed by G1P[8] (25.4%) and G2P[8] (3.2%).

Synthesis, molecular structure and vibrational spectra of a dimeric complex formed by cobalt and glycine.

The structure of [Co(gly)(2)(OH)(2)].1.5(H(2)O) was solved by X-ray diffraction. It crystallizes in the space group P-1, with two independent dimmers in the unit cell. The results for the calculated vibrational spectra are in good agreement with the experimental one. The infrared spectrum and ab initio calculations are consistent with the crystallographic results.

Opportunities to improve antimicrobial use in paediatric intensive care units: a nationwide survey in Spain.

Improving antimicrobial use is a complex process that requires an accurate assessment of ongoing problems and barriers. Paediatric intensive care units (PICU) have seldom been assessed from this perspective. Two Internet-based, self-administered surveys were conducted nationwide in Spain between January and February 2014. The first survey aimed to assess those characteristics of Spanish PICUs that could influence antimicrobial prescribing or antimicrobial stewardship. The second survey targeted Spanish PICU physicians and pursued to assess their attitudes and perceptions regarding antimicrobial resistance and antimicrobial use. Information about 29/39 contacted PICUs was obtained. A total of 114/206 (55.3%) paediatric intensivists responded. PICUs were heterogeneous regarding years since foundation, number of beds, type of patients admitted and staffing. Only 11 (37.9%) PICUs had available e-prescribing systems. Procalcitonin was available in 24 (89.1%) PICUs, but there were no procalcitonin-based protocols in 14 (60.9%) of them. Half of surveyed PICUs had implemented antimicrobial stewardship activities. Ninety-eight of the 114 PICU physicians (86%) who participated considered that antimicrobial resistance was a significantly relevant problem for their daily and that improving antimicrobial use in their PICU should be a priority (103; 90.4%). The main perceived problems regarding antimicrobial use were the excessive use of antimicrobials in patients with nonconfirmed infections and excessive use of broad-spectrum antimicrobials. The most valued antimicrobial stewardship interventions were the implementation of protocols to guide antimicrobial therapy. Spanish PICU doctors are aware of the relevance of the problem of antimicrobial resistance and the need to improve antimicrobial use. Targeted interventions should take into account their difficulties and preferences when feasible.

Inhibition of tumor growth and metastasis of human melanoma by intracellular anti-ATF-1 single chain Fv fragment.

Activating transcription factor-1 (ATF-1) and cAMP-responsive element (CRE)-binding protein (CREB) have been implicated in cAMP and Ca2+-induced transcriptional activation. The expression of the transcription factors CREB and ATF-1 is upregulated in metastatic melanoma cells. However, how overexpression of ATF-1/CREB contributes to the acquisition of the metastatic phenotype remains unclear. Here, the effect of disrupting ATF-1 activity was investigated using intracellular expression of an inhibitory anti-ATF-1 single chain antibody fragment (ScFv). Intracellular expression of ScFv anti-ATF-1 in MeWo melanoma cells caused significant reduction in CRE-dependent promoter activation. In addition, expression of ScFv anti-ATF-1 in melanoma cells suppressed their tumorigenicity and metastatic potential in nude mice. ScFv anti-ATF-1 rendered the melanoma cells susceptible to thapsigargin-induced apoptosis in vitro and caused massive apoptosis in tumors transplanted subcutaneously into nude mice, suggesting that ATF-1 and its associated proteins act as survival factor for human melanoma cells. This is the first report to demonstrate the potential of ScFv anti-ATF-1 as an inhibitor of tumor growth and metastasis of solid tumor in vivo. Oncogene (2000).

Life-threatening orolingual angioedema during thrombolysis in acute ischemic stroke.

BACKGROUND: Orolingual angioedema can occur during thrombolysis with alteplase in stroke patients. However, data about its frequency, severity and the significance of concurrent use of angiotensin-converting-enzyme inhibitors (ACEi) are sparse. OBJECTIVE: (1), to alert to the potentially life-threatening complication of orolingual angioedema. (2), to present CT-scans of the tongue which exclude lingual hematoma. (3), to estimate the frequency of orolingual angioedema. (4), to evaluate the risk associated with the concurrent use of ACEi. METHODS: Single center, databank-based observational study on 120 consecutive patients with i. v. alteplase for acute stroke. Meta-analysis of all stroke studies on alteplase-associated angioedema, which provided detailed information about the use of ACE-inhibitors. Across studies, the Peto odds ratio of orolingual angioedema for "concurrent use of ACEi" was calculated. RESULTS: Orolingual angioedema occurred in 2 of 120 patients (1.7%, 95% CI 0.2-5.9 %). Angioedema was mild in one, but rapidly progressive in another patient. Impending asphyxia prompted immediate intubation. CT showed orolingual swelling but no bleeding. One of 19 (5%) patients taking ACEi had orolingual angioedema, compared to 1 of 101 (1%) patients without ACEi. Medline search identified one further study about the occurrence of alteplase-associated angioedema in stroke patients stratified to the use of ACEi. Peto odds ratio of 37 (95 % CI 8-171) indicated an increased risk of alteplasetriggered angioedema for patients with ACEi (p <0.001). CONCLUSION: Orolingual angioedema is a potentially life-threatening complication of alteplase treatment in stroke patients, especially in those with ACEi. Orolingual hematoma as differential diagnosis can be excluded by CT-scan.

Global identification of genes targeted by DNMT3b for epigenetic silencing in lung cancer.

The maintenance cytosine DNA methyltransferase DNMT1 and de novo methyltransferase DNMT3b cooperate to establish aberrant DNA methylation and chromatin complexes to repress gene transcription during cancer development. The expression of DNMT3b was constitutively increased 5-20-fold in hTERT/CDK4-immortalized human bronchial epithelial cells (HBECs) before treatment with low doses of tobacco carcinogens. Overexpression of DNMT3b increased and accelerated carcinogen-induced transformation. Genome-wide profiling of transformed HBECs identified 143 DNMT3b-target genes, many of which were transcriptionally regulated by the polycomb repressive complex 2 (PRC2) complex and silenced through aberrant methylation in non-small-cell lung cancer cell lines. Two genes studied in detail, MAL and OLIG2, were silenced during transformation, initially through enrichment for H3K27me3 and H3K9me2, commonly methylated in lung cancer, and exert tumor suppressor effects in vivo through modulating cancer-related pathways. Re-expression of MAL and OLIG2 to physiological levels dramatically reduced the growth of lung tumor xenografts. Our results identify a key role for DNMT3b in the earliest stages of initiation and provide a comprehensive catalog of genes targeted for silencing by this methyltransferase in non-small-cell lung cancer.

Cell surface oligosaccharide modulation during differentiation: V. Partial characterization of the regulated surface during substrate adhesion and spreading.

In previous studies with IMR-90 human fetal lung fibroblasts, it was shown that modulation of a small finite number of unique cell surface oligosaccharide structural specificities (as defined by reaction with specific lectins and monoclonal antibodies) define the cellular senescence phenotype. The cell surface oligosaccharide display can be characterized by assessing the epitope density and conformational arrangement of three or four individual carbohydrate specificities. Development of the senescence morphological phenotype was preceded by specific alterations in the cell surface oligosaccharide display. The senescence-dependent changes in these displays are primarily related to the binding affinity (the Kij of the Scatchard analyses) rather than the epitope density (the binding capacity, Rij of the Scatchard analyses). These alterations involve rearrangements within specific carbohydrate classes. In the course of these studies, the observation was made that low-density and contact-inhibited growth-retarded Phase II cells showed similar surface modulation of the oligosaccharide display. This suggests a broader significance for the date in growth regulation. These data suggest a structural/functional relationship between cellular senescence mechanisms and growth control in general. In this study we have investigated the possible role of cell surface oligosaccharide regulation in substrate interactions. Trypsinized cells were studied during substrate adherence, spreading and initiation of growth on control and poly-L-ornithine-treated polystyrene substrate. The cell surface oligosaccharide display was characterized using both biological assays and NMR-based measurements of the mobility of water at the cell surface. Results show that trypsinization does not remove or diminish the oligosaccharide display. The initial adherence of the cells to unmodified substrate is mediated by oligosaccharides. Cellular spreading results in specific changes in the display. Initiation of growth corresponds to further specific changes in the display. These data suggest a mechanistic connection between the cell surface oligosaccharide display and growth control of these fibroblasts.

Invasive pulmonary aspergillosis. MRI, CT, and plain radiographic findings and their contribution for early diagnosis.

A prospective study was conducted in 38 patients with nodular lesions on plain chest radiographs and the clinical suspicion of invasive pulmonary aspergillosis (IPA) to assess the diagnostic accuracy of magnetic resonance imaging (MRI) and computed tomography (CT). For early diagnosis of IPA (clinical signs and symptoms < 10 days), CT scans with demonstration of the halo sign had a high sensitivity (16/22) and specificity (8/8). Magnetic resonance imaging performed at the same time revealed a relatively higher sensitivity (22/22), but a very poor specificity (0/8). Gadolinium-diethylene-triamine-pentaacetic acid (Gd-DTPA) enhanced images did not improve specificity. In the later course of infection (clinical signs and symptoms > 10 days), MRIs showed typical nodular target-like lesions with Gd-DTPA enhancement of the rim area that was not seen in the early course of the disease or in patients with Pseudomonas or staphylococcal infection. In conclusion, MRI findings are not as characteristic as the CT halo sign in diagnosing IPA in the early course of the disease, but the MRI target sign with Gd-DTPA enhancement of the rim area and the "reverse target" on T2-weighted images are strongly suggestive of IPA at a later stage of the disease.

Magnetic resonance diagnosis of the anterior labrum and capsule. Effect of field strength on efficacy.

RATIONALE AND OBJECTIVES: The authors compare the performance of high-field and low-field magnetic resonance (MR) systems in the evaluation of shoulder instability, 35 patients were examined at field strengths of 1.0 T and of 0.2 T. METHODS: Surface coils were used in both systems. Because arthroscopy was used as gold standard, a preselected patient-population was obtained for the study. RESULTS: The sensitivity/specificity/accuracy of MR images acquired at 1.0 T for labrum pathology were 91%/67%/91% and 70%/80%/71% for the capsular complex. Compared with the above, the sensitivity/specificity/accuracy for 0.2 T MR images revealed 91%/67%/91% for the labrum pathology and 63%/80%/66% for the capsular complex respectively. In the evaluation of capsular lesions a comparison between the 0.2 T MR system and the 1.0 T system indicated a higher sensitivity and accuracy for the high-field images. Concerning labral lesions, the sensitivity and accuracy of the 0.2 T MR imager and the 1.0 T imager were comparable. CONCLUSIONS: Given differences in imaging protocols, imaging at 0.2 T does not adversely affect the assessment of shoulder instability when compared with imaging at 1.0 T. These preliminary results warrant more extensive clinical comparison of results obtained at different magnetic field strengths.

Attitudes of physicians practicing in New Mexico toward gay men and lesbians in the profession.

PURPOSE: To examine the attitudes of physicians practicing in New Mexico toward gay and lesbian medical students, house officers, and physician colleagues. METHOD: In May 1996, the authors mailed a questionnaire with demographic and attitude questions to 1,949 non-federally employed physicians practicing in New Mexico. The questionnaire consisted of questions dealing with medical school admission, residency training, and referrals to colleagues. The response rate was 53.6%. RESULTS: Of all the responding physicians, 4.3% would refuse medical school admission to applicants known to be gay or lesbian. Respondents were most opposed to gay and lesbian physicians' seeking residency training in obstetrics and gynecology (10.1%), and least opposed to their seeking residency training in radiology (4.3%). Disclosure of homosexual orientation would also threaten referrals to gay and lesbian obstetrician-gynecologists (11.4%) more than to gay or lesbian physicians in other specialties. CONCLUSION: Physicians' attitudes toward gay and lesbian medical students, house officers, and physician colleagues seem to have improved considerably from those reported previously in the literature. However, gay men and lesbians in medicine continue to face opposition in their medical training and in their pursuit of specialty practice.

Uptake of porcine rubulavirus (LPMV) by PK-15 cells.

BACKGROUND: The porcine virus denominated La Piedad Michoacan Virus (LPMV) is a member of the family Paramyxoviridae and is the cause of a disease in pigs present only in Mexico. The disease is characterized by meningoencephalitis and respiratory distress in young pigs, epididymitis and orchitis in boars, and reproductive failure and abortion in sows. METHODS: The cytopathology, morphology, and distribution of the hemagglutination neuraminidase (HN) and nucleoprotein (NP) proteins of LPMV were investigated following inoculation into PK-15 cells. The cytopathic effect was characterized by cytoplasmic vacuolation and the formation of syncytia and cytoplasmic inclusion bodies. RESULTS: In immunofluorescence assays using a monoclonal antibody (MAb) against the HN protein at 5-60 min post-infection (early infection), a diffuse immunofluorescence was observed near the cell membrane and adjacent to the nuclear membrane. At 24 h post-infection (late infection), a dust-like immunofluorescence was observed throughout the cytoplasm. LPMV-infected cells incubated with the MAb against the NP protein showed punctate cytoplasmic fluorescence during the early stages of infection. At the late infection stage, these fluorescent particles became larger and were seen predominantly in the cytoplasm of syncytia. This pattern was also apparent by immunohistochemical labeling and immunogold electron microscopy. The latter technique revealed that HN protein was diffusely distributed throughout the cytoplasm. When using the MAb against the NP protein, nucleocapsid organization was the most prominent feature and resulted in the formation of cytoplasmic inclusion bodies visible by light and electron microscopy. Immunogold labeling of purified nucleocapsids was shown by electron microscopy. Virus particles and nucleocapsids were morphologically similar to members of the Paramyxoviridae family. CONCLUSIONS: The morphologic characteristics of the virions and the distribution patterns of the HN and NP proteins in PK-15 infected cells indicate that the mechanisms of LPMV replication are generally similar to those of the members of the Paramyxoviridae family.