Pre-existing root cementum may promote cementoblast differentiation of human periodontal ligament cells

OBJECTIVES

To observe whether preserved healthy cementum could promote differentiation of human periodontal ligament cells to cementoblasts.

MATERIALS AND METHODS

Symmetrical root slices from each healthy premolar were distributed into either the control group (cementum removed) or test group (cementum preserved). After isolation and characterization, human periodontal ligament cells were inoculated onto root slices for 7 days co-culture. Two slices per group were studied for cell morphology by scanning electronic microscopy. Twenty-three slices were detected for expression of cementum attachment protein and cementum protein 23, two putative cementoblast markers, by real-time polymerase chain reaction. Twenty slices were transplanted into nude mice and analysed using histology and immunohistochemistry for osteopontin and bone sialoprotein expression after 8 weeks.

RESULTS

Cells of the test group had smoother fibroblast morphology and higher cementum protein 23 and cementum attachment protein expression than those of the control group (P < 0.01). In the test group, 14 root slices revealed cementum-like matrix formation resting on old cementum; no splits were observed between newly formed matrix and old cementum. In the control group, 17 specimens had fibrous tissue formation along the root surface and varying width of splits could be seen between new fibrous tissue and dentine surface. Only three specimens demonstrated presence of newly formed thin cementum-like matrix. Newly formed cementum-like matrix was positive for osteopontin and bone sialoprotein.

CONCLUSIONS

The results demonstrate that healthy root cementum may promote differentiation of human periodontal ligament cells towards cementoblasts.

Inhibition of osteoclastogenesis by prolyl hydroxylase inhibitor dimethyloxallyl glycine

Studies examining the effects of hypoxia upon osteoclast biology have consistently revealed a stimulatory effect; both osteoclast differentiation and resorption activity have been shown to be enhanced in the presence of hypoxia. In the present study we examined the effects of the hypoxia mimetics dimethyloxallyl glycine (DMOG) and desferrioxamine (DFO) upon osteoclastogenesis. In contrast to hypoxia, our studies revealed a dose-dependent inhibition of osteoclast formation from macrophages treated with DMOG and DFO. Moreover, expression of a constitutively active form of hypoxia-inducible factor 1alpha (HIF-1alpha) did not enhance osteoclastogenesis and actually attenuated the differentiation process. DMOG did not affect cell viability or receptor activator of nuclear factor kappaB ligand (RANKL)-dependent phosphorylation of mitogen-activated protein (MAP) kinases. However, RANKL-dependent transcription of tartrate-resistant acid phosphatase (TRAP) was reduced in the presence of DMOG. Additionally, DMOG promoted transcription of the pro-apoptotic mediator B-Nip3. These studies suggest that a hypoxia-responsive factor other than HIF-1alpha is necessary for enhancing the formation of osteoclasts in hypoxic settings.

Efficacy of a long-term antibiotic treatment in patients with a chronic Tick Associated Poly-organic Syndrome (TAPOS)

SETTINGS

Despite a now codified antibiotic treatment for Lyme disease, a significant proportion of patients treated according to recommendations complain of persistent signs and symptoms. The pathophysiological mechanisms which underlie this syndrome of post-treatment chronic systemic illness remain unclear. For some physicians post-treatment symptoms indicate a persistent infection requiring prolonged antibiotic therapy. For others, there is no benefit from antimicrobial therapy. The difficulty of assessment encountered in studies is significant because many symptoms are subjective. We think that the term "chronic Lyme disease" is not appropriate and should be replaced by chronic "tick associated poly-organic syndrome" (TAPOS).

OBJECTIVE

This open-label prospective study was made on a group of 100 patients having followed a medical treatment for a chronic TAPOS and to evaluate their evolution under prolonged antibiotic treatment.

RESULTS

The medical management was found to be effective for symptoms, especially for patients with a high probability of chronic TAPOS (NEJM score). Patients with post tick-bite symptoms, which often worsens their quality of life, deserve particular attention.

CONCLUSION

This study had methodological limitations but could help in terms of feasibility, choice of inclusion criteria, and design of follow-up for a future randomized, double blind study to test for an optimal management of TAPOS.

PEGylated adenovirus for targeted gene therapy

Bifunctional polyethylene glycol (PEG) molecules provide a novel approach to retargeting viral vectors without the need to genetically modify the vector. Modification of the surface of adenovirus with heterofunctional PEG allows further modification of the capsid with ligands. In addition, heterofunctional PEG modification ablates the normal tropism of the virus and reduces transduction of non-target tissues in vivo. Moreover, the addition of PEG chains to the surface of the virus shields antigen-binding sites, significantly reducing the susceptibility of the virus to antibody neutralization. Finally, T cell subsets from mice exposed to the PEGylated vector demonstrate a marked decrease in Th1 and Th2 responses, suggesting that PEG modification may help reduce the immune response to the vector.

Trends and predictors of HIV-positive community attachment among PLWHA

Communities most affected by HIV/AIDS have been instrumental in shaping Australia's responses to the threat of the epidemic. There are recent signs that levels of engagement in communities based around HIV-positivity have changed: a diminished sense of an AIDS crisis, the relative success of highly active antiretroviral therapy (HAART), and an increasing individualization of the HIV experience may be contributing to changes in the way HIV-community is experienced. In this paper, we explore levels of engagement in HIV-positive community among a cohort of people living with HIV/AIDS (PLWHA) and seek to explain why some PLWHA engage in an HIV-positive community while others do not. Using multivariate logistic regression, we found that three factors were independently related to feeling part of an HIV-positive community: having been diagnosed with HIV prior to the advent of HAART; having more recently taken Bactrim or Septrin for PCP; and finding it easier to take 'pills' on time. Taken together, these results suggest that both historical effects, such as the introduction of HAART, and effects related to living with HIV, such as the experience of an AIDS-related illness, help explain HIV-positive community engagement among PLWHA.

Steroid-induced ptosis: case studies and histopathologic analysis

PURPOSE

The purpose of this study was to review patients who developed ptosis after subtenon's steroid injection and to study the mechanism of steroid-induced ptosis in an animal model.

METHODS

Part 1. Twenty-two patients with uveitis who had received posterior subtenon's triamcinolone acetonide injections were retrospectively reviewed. Demographics, type of uveitis, type and number of surgeries, pre and postoperative marginal reflex distance (MRD1), and clinical outcomes were evaluated. Part 2. Study of rabbit levator muscle and aponeurosis histopathology after subtenon's triamcinolone injection was performed.

RESULTS

Part 1. The average age was 44.6 years (range: 14-85 years) with a mean follow-up of 14 months. The most common causes of uveitis included uveitis after cataract extraction (five), pars planitis (three), multifocal choroiditis (three), and juvenile rheumatoid arthritis (three). The average time to documented onset of ptosis was 13.9 months (range: 0-49 months). In patients who received only one steroid injection, the average time to ptosis recorded was 2.7 months (range: 0-6 months). Seventeen patients underwent ptosis repair. Part 2. No ptosis was noted in the experimental and control groups. Histopathologic analysis of levator tissues revealed no significant difference in atrophy or degree of inflammation between experimental and control groups.

CONCLUSIONS

Ptosis following subtenon's steroid injection ranged from mild to moderate and occurred a few months after steroid injection. Prior studies of muscles and periocular tissues exposed to corticosteroids demonstrated degenerative muscle changes; our studies revealed no histopathologic changes in the levator muscle or aponeurosis.

Gene transfer of human acid sphingomyelinase corrects neuropathology and motor deficits in a mouse model of Niemann-Pick type A disease

Niemann-Pick type A disease is a lysosomal storage disorder caused by a deficiency in acid sphingomyelinase (ASM) activity. Previously we showed that storage pathology in the ASM knockout (ASMKO) mouse brain can be corrected by adeno-associated virus serotype 2 (AAV2)-mediated gene transfer. The present experiment compared the relative therapeutic efficacy of different recombinant AAV serotype vectors (1, 2, 5, 7, and 8) using histological, biochemical, and behavioral endpoints. In addition, we evaluated the use of the deep cerebellar nuclei (DCN) as a site for injection to facilitate global distribution of the viral vector and enzyme. Seven-week-old ASM knockout mice were injected within the DCN with different AAV serotype vectors encoding human ASM (hASM) and then killed at either 14 or 20 weeks of age. Results showed that AAV1 was superior to serotypes 2, 5, 7, and 8 in its relative ability to express hASM, alleviate storage accumulation, and correct behavioral deficits. Expression of hASM was found not only within the DCN, but also throughout the cerebellum, brainstem, midbrain, and spinal cord. This finding demonstrates that targeting the DCN is an effective approach for achieving widespread enzyme distribution throughout the CNS. Our results support the continued development of AAV based vectors for gene therapy of the CNS manifestations in Niemann-Pick type A disease.

Colonic motility diagnosis based on colonic pressure

Manometry of the alimentary tract is a valuable and widely used means to evaluate and diagnose the function of the alimentary tract. However, the measurement can be inconvenient due to the invasive method used, and the many factors affecting results. Research on colonic pressure data is even more insufficient. This paper deals with colonic pressure data via an improved method ensuring that pressure data of the whole colon is available. The data is analysed based on the learning vector quantization (LVQ) method. Testing results show that this method distinguishes the normal data and the abnormal data, consistently with the original diagnoses. This method can serve as an assistant diagnosis of colonic motility and contributes to further research on colonic motility based on pressure data.

Targeting adenoviral vectors using heterofunctional polyethylene glycol FGF2 conjugates

Bifunctional PEG (polyethylene glycol) molecules provide a novel approach to retargeting viral vectors without the need to genetically modify the vector. In a previous report we showed that modification of the viral capsid by the addition of a peptide with binding preference for differentiated ciliated airway epithelia allowed gene delivery to those cells by a novel entry pathway. Here we demonstrate further the versatility of this method by coupling a protein, FGF2, to the surface of an adenovirus (Ad). This modification results in the elimination of the endogenous tropism of the virus and confers upon the virus a novel route of entry. Adenoviral vectors modified by the addition of FGF2 show enhanced efficiency of transduction of the ovarian cancer cell line SKOV3.ip1. This enhancement in transduction is dependent on the binding of the coupled FGF2 to its high-affinity receptor and is independent of coxsackie and adenovirus viral receptors. In an intraperitoneal model of ovarian cancer, Ad/PEG/FGF2 generates increased transgene expression in tumor tissue compared to unmodified Ad. Furthermore, polymer modification of adenovirus vectors results in reduced localization of adenovirus to nontarget tissues and a marked decrease in Th1 and Th2 T cell responses. In conclusion, the approach described here may lead to the development of a gene therapy vector capable of targeting a therapeutic gene to diseased cells, while minimizing toxicity and expression in other tissues.

The LN54 radiation hybrid map of zebrafish expressed sequences

To increase the density of a gene map of the zebrafish, Danio rerio, we have placed 3119 expressed sequence tags (ESTs) and cDNA sequences on the LN54 radiation hybrid (RH) panel. The ESTs and genes mapped here join 748 SSLp markers and 459 previously mapped genes and ESTs, bringing the total number of markers on the LN54 RH panel to 4226. Addition of these new markers brings the total LN54 map size to 14,372 cR, with 118 kb/cR. The distribution of ESTs according to linkage groups shows relatively little variation (minimum, 73; maximum, 201). This observation, combined with a relatively uniform size for zebrafish chromosomes, as previously indicated by karyotyping, indicates that there are no especially gene-rich or gene-poor chromosomes in this species. We developed an algorithm to provide a semiautomatic method for the selection of additional framework markers for the LN54 map. This algorithm increased the total number of framework markers to 1150 and permitted the mapping of a high percentage of sequences that could not be placed on a previous version of the LN54 map. The increased concentration of expressed sequences on the LN54 map of the zebrafish genome will facilitate the molecular characterization of mutations in this species.

Functional activation of the extensor carpi radialis muscles in humans

OBJECTIVES

To assess activity of radial wrist extensors caused by isometric radial deviation and extension by using magnetic resonance imaging (MRI) and to assess measures that might be used to normalize T2-weighted data.

DESIGN

Two-way analysis of variance (ANOVA) design.

SETTING

Laboratory and children's hospital.

PARTICIPANTS

Three healthy volunteers.

INTERVENTIONS

Ten repetitions of 10-second randomly ordered 30% or 60% of maximum voluntary isometric contractions toward wrist extension or radial deviation.

MAIN OUTCOME MEASURES

Average T2 values from T2-weighted MR images of the extensor carpi radialis brevis (ECRB) and the extensor carpi radialis longus (ECRL), flexor digitorum profundus (FDP), and radius marrow were determined across 7 sections and 4 exercise bouts and a preexercise condition.

RESULTS

Significant differences across task and across sections were determined. Post hoc analysis revealed differences in activity between proximal and distal ECRB and ECRL during an exercise and differential activation of the same muscle across the 2 exercise tasks. Bone marrow and FDP did not show task-related changes. The range of average T2 values of bone marrow across sections was greater than a muscle (FDP) that was not the target of the exercise protocol. However, FDP did show small but significant differences across sections.

CONCLUSIONS

T2-weighted MR images can be used to study muscle activation at 30% and 60% of maximum voluntary contractions. The use of inactive muscle and bone marrow for normalizing data requires further investigation.

Mutual information analysis as a tool to assess the role of aneuploidy in the generation of cancer-associated differential gene expression patterns

Most human tumors are characterized by: (1) an aberrant set of chromosomes, a state termed aneuploidy; (2) an aberrant gene expression pattern; and (3) an aberrant phenotype of uncontrolled growth. One of the goals of cancer research is to establish causative relationships between these three important characteristics. In this paper we were searching for evidence that aneuploidy is a major cause of differential gene expression. We describe how mutual information analysis of cancer-associated gene expression patterns could be exploited to answer this question. In addition to providing general guidelines, we have applied the proposed analysis to a recently published breast cancer-associated gene expression matrix. The results derived from this particular data set provided preliminary evidence that mutual information analysis may become a useful tool to investigate the link between differential gene expression and aneuploidy.

Serine protease inhibitor causes F-actin redistribution and inhibition of calcium-mediated secretion in pancreatic acini

BACKGROUND & AIMS

The present study was undertaken to evaluate the role of serine proteases in regulating digestive enzyme secretion in pancreatic acinar cells.

METHODS

Isolated acini were stimulated by various secretagogues in the presence or absence of cell-permeant serine protease inhibitors 4-(2-aminoethyl)-benzenesulfonyl fluoride and N(alpha)-p-tosyl-L-phenylalanine chloromethyl ketone. F-actin distribution was studied after staining with rhodamine phalloidin.

RESULTS

Both cell-permeant serine protease inhibitors blocked amylase secretion in response to secretagogues that use calcium as a second messenger (e.g., cerulein, carbamylcholine, and bombesin) but not to those that use adenosine 3',5'-cyclic monophosphate (cAMP) as a second messenger (e.g., secretin and vasoactive intestinal polypeptide). Incubation of the acini with these inhibitors also resulted in a dramatic redistribution of the F-actin cytoskeleton. This redistribution was energy dependent. Similar redistribution of F-actin from the apical to the basolateral region was also observed when acini were incubated with a supramaximally stimulating concentration of cerulein, which is known to inhibit secretion.

CONCLUSIONS

These results suggest that a serine protease activity is essential for maintaining the normal apical F-actin distribution; its inhibition redistributes F-actin from the apical to the basolateral region and blocks secretion induced by secretagogues that act via calcium. cAMP reverses the F-actin redistribution and hence cAMP-mediated secretion is not affected.

Pseudomonas aeruginosa in vitro corneal isolate sensitivity to ofloxacin, ciprofloxacin, and trovafloxacin: a comparative study

PURPOSE

To compare sensitivity of Pseudomonas aeruginosa corneal isolates to ofloxacin, ciprofloxacin, and trovafloxacin.

METHODS

Sensitivities of P. aeruginosa corneal isolates to each antibiotic from the periods 1985 to 1987 (n = 32) and 1995 to 1999 (n = 85) were evaluated in vitro with E tests (AB Biodisk; Remel, Lenexa, Kansas).

RESULTS

Overall, the percent of P. aeruginosa corneal isolates sensitive in vitro to ofloxacin (106/117, 90.6%) was significantly less than to ciprofloxacin (113/117, 96.6%, P =.016) and trovafloxacin (113/117, 96.6%, P =.016). We observed trends of decreasing sensitivity to ciprofloxacin and trovafloxacin, which were not statistically significant. Sensitivity to ofloxacin remained unchanged; however, sensitivity to ofloxacin was always less than sensitivity to ciprofloxacin and trovafloxacin.

CONCLUSION

Although in vitro susceptibilities may not correlate with in vivo efficacy, our data suggest that ciprofloxacin and trovafloxacin are superior to ofloxacin in the treatment of P. aeruginosa keratitis.

Organization of regions with amphiphilic alpha-helical potential within the three-dimensional structure of beta-sheet proteins

The observation that strong amphiphilic alpha-helical potential exists in all proteins, including beta-sheet proteins, has given rise to the idea that alpha-helical intermediates may be critical to the folding paths of all proteins. Here we report that regions with amphiphilic alpha-helical potential in beta-sheet proteins are regularly spaced within the native structure of the proteins at an average interval of about 13 A. This regular spacing did not occur when the location of amphiphilic regions was randomly assigned (p = 0.0056), suggesting some degree of organization with respect to the native fold. However, in the native structure of various non-homologous proteins that contain the same fold, the location of the regions with amphiphilic alpha-helical potential was not conserved. Further, there was no apparent association of amphiphilic alpha-helical potential with any particular type of secondary structure, confirming that this potential is not involved in maintenance of native structure and suggesting that it may be associated with a highly adaptable process.

Economic and outcomes assessment of magnetic resonance imaging in the evaluation of headache

We sought to evaluate the economic impact and diagnostic utility of magnetic resonance imaging (MRI) in the management of patients with headache and nonfocal physical examinations. Computerized medical records were retrospectively reviewed of 1,233 patients presenting for MRI of headache at our institution over a 3-year period (1992-1995). Patients with focal findings at physical examination, prior brain surgery, head trauma, or immunocompromise were excluded. A model was developed to assess the cost associated with the MR test results, and actual average institutional costs of performing an examination applied. Correlative statistical analysis of referring specialties and positive tests was also performed. Three hundred twenty-eight patients who met the above criteria were retained in the sample. One hundred sixty-three patients (50%) had negative MR test results. Of the 50% of patients with positive studies, only 5 (1.5%) had clinically significant MR results. The average cost of an MR examination was 517 dollars (1998 dollars). The cost per clinically significant managed case detected was 34,535 dollars. No statistically significant difference was found among referring specialties and clinically significant MR results. Our results indicate that MRI of nonfocal headache yields a low percentage of positive clinically significant results and has limited cost-effectiveness. Referring specialty had no significant bearing on these outcomes, regardless of specialist experience.

Transcriptional regulation of RANTES expression in T lymphocytes

We first identified the RANTES chemokine as part of a search for genes expressed by T lymphocytes "late", 3-5 days, after T-cell activation. The kinetics of expression of RANTES and a small number of other genes are unusual and the mechanism of such delayed expression is unknown. In order to uncover a mechanism for such "late" expression, we identified and characterized the RANTES promoter and a novel transcription factor regulating RANTES expression in T lymphocytes. RANTES factor of late activated T lymphocytes (RFLAT)-1 is a member of the Krüppel-like family of transcription factors. Like RANTES, RFLAT-1 expression is "late" after T-cell activation. But, unlike RANTES, regulation of RFLAT-1 expression appears to be translational rather than transcriptional.

MR imaging of pentalogy of Cantrell variant with an intact diaphragm and pericardium

We present a case of a neonate with the stigmata for pentalogy of Cantrell with the exception of diaphragmatic and pericardial defects. Diagnosing most of the anomalies in this rare syndrome can be accomplished using conventional modalities in radiology, but difficulties may arise determining diaphragmatic continuity. Accurate, early diagnosis of components of this syndrome is vital for surgical planning and assessing prognostic factors.