A synthetic nanofibrillar matrix promotes in vivo-like organization and morphogenesis for cells in culture

The purpose of this study was to design a synthetic nanofibrillar matrix that more accurately models the porosity and fibrillar geometry of cell attachment surfaces in tissues. The synthetic nanofibrillar matrices are composed of nanofibers prepared by electrospinning a polymer solution of polyamide onto glass coverslips. Scanning electron and atomic force microscopy showed that the nanofibers were organized into fibrillar networks reminiscent of the architecture of basement membrane, a structurally compact form of the extracellular matrix (ECM). NIH 3T3 fibroblasts and normal rat kidney (NRK) cells, when grown on nanofibers in the presence of serum, displayed the morphology and characteristics of their counterparts in vivo. Breast epithelial cells underwent morphogenesis to form multicellular spheroids containing lumens. Hence the synthetic nanofibrillar matrix described herein provides a physically and chemically stable three-dimensional surface for ex vivo growth of cells. Nanofiber-based synthetic matrices could have considerable value for applications in tissue engineering, cell-based therapies, and studies of cell/tissue function and pathology.     

Inhibition of KATP channel activity augments baroreflex-mediated vasoconstriction in exercising human skeletal muscle

In the present investigation we examined the role of ATP-sensitive potassium (K_ATP) channel activity in modulating carotid baroreflex (CBR)-induced vasoconstriction in the vasculature of the leg. The CBR control of mean arterial pressure (MAP) and leg vascular conductance (LVC) was determined in seven subjects (25 ± 1 years, mean ± s.e.m. ) using the variable-pressure neck collar technique at rest and during one-legged knee extension exercise. The oral ingestion of glyburide (5 mg) did not change mean arterial pressure (MAP) at rest (86 versus 89 mmHg, P > 0.05), but did appear to increase MAP during exercise (87 versus 92 mmHg, P = 0.053). However, the CBR–MAP function curves were similar at rest before and after glyburide ingestion. The CBR-mediated decrease in LVC observed at rest (∼39%) was attenuated during exercise in the exercising leg (∼15%, P < 0.05). Oral glyburide ingestion partially restored CBR-mediated vasoconstriction in the exercising leg (∼40% restoration, P < 0.05) compared to control exercise. These findings indicate that K_ATP channel activity modulates sympathetic vasoconstriction in humans and may prove to be an important mechanism by which functional sympatholysis operates in humans during exercise.     

Parent-of-origin effect in the segregation analysis of bipolar affective disorder families

OBJECTIVE: The purpose of this study is to test for heterogeneity in bipolar families based on the differential parental transmission of disease. METHODS: Complex segregation analyses of 260 bipolar families, ascertained by the Johns Hopkins Bipolar Disorder Study, was performed based on the evidence for a parent-of-origin effect in the inheritance pattern by using REGD in Statistical Analysis for Genetic Epidemiology, Release 3.1 program. RESULTS: A Mendelian dominant model provided the best explanation in 57 paternal pedigrees (pedigrees with an affected paternal lineage). No evidence of Mendelian inheritance existed among 141 pedigrees showing maternal transmission. A likelihood ratio test for heterogeneity on the basis of best-fitting Mendelian dominant model showed significant differences between these two groups. CONCLUSION: These results suggest that pedigrees with no evidence of maternal transmission of bipolar disorder may represent a unique genetic subgroup of multiplex bipolar families.     

Spatial and Frequency Differences of Neuromagnetic Activities Between the Perception of Open- and Closed-class Words

The present study investigated the spatial and frequency differences of neuromagnetic activities between the perception of open- and closed-class words by using a 275-channel whole head magnetoencephalography (MEG) system. Two groups of words, 110 open-class and 110 closed-class, were presented visually and auditorily simultaneously. The data of 12 healthy subjects were analyzed with synthetic aperture magnetometry (SAM) which can identify the frequency-dependent volumetric distribution of evoked magnetic fields (EMFs). Both vocabulary classes elicited spectral power changes in the left inferior frontal gyrus (Broca’s area) and left posterior-superior temporal gyrus (Wernicke’s area) within 70–120 Hz. However, the open-class words elicited event-related desynchronization (ERD) while the closed-class words elicited event-related synchronization (ERS) in the two areas within 70–120 Hz. In addition, the open-class words also elicited ERS in the right inferior frontal gyrus, right middle frontal gyrus and right inferior parietal lobe within 1–8 Hz, but the closed-class words only elicited ERD in the right inferior frontal gyrus within 1–8 Hz. Furthermore, there were ERD in the right posterior-superior temporal gyrus within 120–200 Hz for the open-class words, but not for the closed-class words. These results indicate that open- and closed-class words are processed differently in the brain, not only in the anatomical substrates, but also in the frequency range of neuromagnetic activity.     

A 12-Mb Complete Coverage BAC Contig Map in Human Chromosome 16p13.1–p11.2

We have constructed a complete coverage BAC contig map that spans a 12-Mb genomic segment in the human chromosome 16p13.1-p11.2 region. The map consists of 68 previously mapped STSs and 289 BAC clones, 51 of which-corresponding to a total of 7.721 Mb of genomic DNA-have been sequenced, and provides a high resolution physical map of the region. Contigs were initially built based mainly on the analysis of STS contents and restriction fingerprint patterns of the clones. To close the gaps, probes derived from BAC clone ends were used to screen deeper BAC libraries. Clone end sequence data obtained from chromosome 16-specific BACs, as well as from public databases, were used for the identification of BACs that overlap with fully sequenced BACs by means of sequence match. This approach allowed precise alignment of clone overlaps in addition to restriction fingerprint comparison. A freehand contig drawing software tool was developed and used to manage the map data graphically and generate a real scale physical map. The map we present here is approximately 3.5 x deep and provides a minimal tiling path that covers the region in an array of contigous, overlapping BACs.     

Porphyromonas gingivalis-host interactions in a Drosophila melanogaster model

Porphyromonas gingivalis is a Gram-negative obligate anaerobe that has been implicated in the etiology of adult periodontitis. We recently introduced a Drosophila melanogaster killing model for examination of P. gingivalis-host interactions. In the current study, the Drosophila killing model was used to characterize the host response to P. gingivalis infection by identifying host components that play a role during infection. Drosophila immune response gene mutants were screened for altered susceptibility to killing by P. gingivalis. The Imd signaling pathway was shown to be important for the survival of Drosophila infected by nonencapsulated P. gingivalis strains but was dispensable for the survival of Drosophila infected by encapsulated P. gingivalis strains. The P. gingivalis capsule was shown to mediate resistance to killing by Drosophila antimicrobial peptides (Imd pathway-regulated cecropinA and drosocin) and human beta-defensin 3. Drosophila thiol-ester protein II (Tep II) and Tep IV and the tumor necrosis factor (TNF) homolog Eiger were also involved in the immune response against P. gingivalis infection, while the scavenger receptors Eater and Croquemort played no roles in the response to P. gingivalis infection. This study demonstrates that the Drosophila killing model is a useful high-throughput model for characterizing the host response to P. gingivalis infection and uncovering novel interactions between the bacterium and the host.     

Are three sputum acid-fast bacillus smears necessary for discontinuing tuberculosis isolation?

To evaluate the efficacy of three sputum acid-fast bacillus (AFB) smears to rule out pulmonary tuberculosis, sputum AFB smear and culture results were analyzed at two university-affiliated teaching hospitals. The negative predictive value of the smear increased by only 0.2% on days 2 and 3 each, indicating that in low-prevalence populations, there is limited value in requiring three negative sputum AFB smears before discontinuing tuberculosis isolation.     

Apparent replication of suggestive linkage on chromosome 16 in the NIMH genetics initiative bipolar pedigrees

Analyses of a replication sample of families collected as part of the National Institute of Mental Health (NIMH) Genetics Initiative for bipolar disorder provide further evidence for linkage to a region of chromosome 16. Families who had a bipolar I (BPI) proband and at least one BPI or schizoaffective, bipolar type (SABP) first-degree relative were ascertained for the purpose of identifying genes involved in bipolar affective disorder. A series of hierarchical models of affected status was used in linkage analyses. Initial genetic analyses of chromosomes 3, 5, 15, 16, 17, and 22, completed at Indiana University in 540 subjects from 97 families, suggested evidence of linkage to chromosomes 5, 16, and 22 [Edenberg et al., 1997: Am J Med Genet 74:238-246]. Genotyping was subsequently performed on these chromosomes in a replication sample of 353 individuals from 56 families. Nonparametric linkage analyses were performed using both affected relative and sibling pair methods. Analyses in the new sample on chromosome 16, using the broadest model of affected status, corroborate previously reported suggestive linkage to the marker D16S2619. Combining the initial and replication samples further increased the evidence of linkage to this region, with a peak lod score of 2.8.