Deviation from Archie's law in partially saturated porous media: Wetting film versus disconnectedness of the conducting phase

We experimentally study the electrical transport in partially water-saturated pore network. The porous medium under investigation is a Fontainebleau sandstone, characterized by x-ray tomography. We show the existence of two electrical conductivity regimes. At high water saturation, the electric resistivity follows a well-known Archie law. Below a water saturation S_{w} approximately 0.2 , a strong negative deviation from this Archie law is observed. We attribute this transition to the existence of "a thick liquid film," assuring the ionic conduction in the low saturation regime. A numerical simulation is proposed to confirm this scenario. Two possible protocols are used to distribute the brine phase in the pore network of a three-dimensional microtomography image. The first one is based on a minimization of the interfacial energy. The second takes into account a quasistatic capillary displacement. The classical random-walk algorithm is used to compute the electric conductivity at various water saturations. Without the "thick film," both of the two fluid-placing protocols show a disconnectedness transition of the brine phase when S_{w}<0.2 . Adding this "film" to solid surface, the electrical continuity is maintained. The bending down trend is correctly reproduced, showing that in this range, the electric response cannot be described by a power law as usual.

In vitro priming recapitulates in vivo HIV-1 specific T cell responses, revealing rapid loss of virus reactive CD4 T cells in acute HIV-1 infection

BACKGROUND

The requirements for priming of HIV-specific T cell responses initially seen in infected individuals remain to be defined. Activation of T cell responses in lymph nodes requires cell-cell contact between T cells and DCs, which can give concurrent activation of T cells and HIV transmission.

METHODOLOGY

The study aim was to establish whether DCs pulsed with HIV-1 could prime HIV-specific T cell responses and to characterize these responses. Both infectious and aldrithiol-2 inactivated noninfectious HIV-1 were compared to establish efficiencies in priming and the type of responses elicited.

FINDINGS

Our findings show that both infectious and inactivated HIV-1 pulsed DCs can prime HIV-specific responses from naïve T cells. Responses included several CD4(+) and CD8(+) T cell epitopes shown to be recognized in vivo by acutely and chronically infected individuals and some CD4(+) T cell epitopes not identified previously. Follow up studies of acute and recent HIV infected samples revealed that these latter epitopes are among the earliest recognized in vivo, but the responses are lost rapidly, presumably through activation-induced general CD4(+) T cell depletion which renders the newly activated HIV-specific CD4(+) T cells prime targets for elimination.

CONCLUSION

Our studies highlight the ability of DCs to efficiently prime naïve T cells and induce a broad repertoire of HIV-specific responses and also provide valuable insights to the pathogenesis of HIV-1 infection in vivo.

Healthy Israel 2020: a visionary national health targeting initiative

This article describes the development of a national health targeting initiative entitled 'Healthy Israel 2020' which was created to enhance the health and wellbeing of Israelis through a variety of health promotion and disease prevention interventions. This initiative builds upon the experience of two major worldwide targeting efforts, "Health People 2010" of the US and the World Health Organization's Health21', as well as lessons learned from other countries. Important philosophical underpinnings are highlighted, particularly the evidence-based nature of the process. Real-world organizational and policy challenges and creative solutions are presented. It is hoped that this report will be of value to others in Israel and elsewhere who are interested in improving the health of their nations.

Sequence variation occurs in CD4 epitopes during early HIV infection

OBJECTIVE

To determine whether viral sequence variation occurs in HIV-specific CD4 epitopes during early HIV infection.

METHODS

Gag, Nef, and integrase (Int) sequences were obtained from the plasma of 7 subjects identified during acute HIV-1 infection. Changes in the viral sequence were determined based on comparison of sequences obtained at 2 time points during early infection. Peptide-specific CD4+ T-cell responses were measured at matched time points using interferon-gamma enzyme-linked immunosorbent spot assays to identify CD4 epitopes.

RESULTS

An average of 4 mutations were identified per subject. The majority of the mutations were nonsynonymous and resulted in a total of 6 amino acid changes in Gag, 7 changes in Nef, and 6 changes and a deletion in Int. Half of the sequence changes were within recognized CD4 epitopes. Mutations within CD4 epitopes were coincident with changes in the peptide-specific CD4 response.

CONCLUSION

These data indicate that sequence variation occurs within recognized CD4 epitopes during early HIV infection. Furthermore, it suggests that mutations within HIV-specific CD4 epitopes may affect T helper cell function.

21. Optimal care in rheumatoid arthritis: Preliminary findings from a focus group study

The objective of our work was to identify facilitators of optimal care, as well as potential barriers, for patients with rheumatoid arthritis (RA). The design was a focus group study. Individuals with established RA were identified through invitation letters sent using a random sample of the Quebec Arthritis Society mailing list. Patients were eligible for participation if they had a diagnosis of RA confirmed by a rheumatologist and if they had sought care within the McGill Réseau Universitaire Intégré de Santé network. We planned a series of focus group meetings (90 minutes each) to obtain sufficient data in terms of spectrum of ideas. In each moderator-led group, participants were asked to discuss five questions related to quality care. A co-moderator was available to document non-verbal communication, with audio-taping of all sessions and professional transcription for data analysis. Qualitative content analysis, based on grounded theory, was the chosen means of identifying recurring themes and categories. Two focus group sessions have been completed with two more scheduled. Preliminary findings indicate the importance of good communication between family physicians, specialists, and allied health care workers. Final coding of transcripts and computer-assisted content analysis is being completed. However it appears that focus group may be useful in studying optimal care for chronic diseases such as RA. Our preliminary findings emphasize the necessity of good communication among health care providers. Ultimately we hope to generate knowledge that can be transformed into better health for Canadians with arthritis and other chronic diseases.

When race matters: disagreement in pain perception between patients and their physicians in primary care

Patients and physicians often disagree in their assessment of pain intensity. This study explores the impact of patient factors on underestimation of pain intensity in chronic noncancer pain. We surveyed patients and their physicians in 12 primary care centers. To measure pain intensity, patients completed an 11-point numeric rating scale for which pain scores range from 0 (no pain) to 10 (unbearable pain). Physicians rated patients' pain on the same scale. We defined disagreement of pain intensity as underestimation or overestimation by 22 points. Of 601 patients approached, 463 (77%) completed the survey. The majority of participants were black (39%) or white (47%), 67% were female, and the mean age was 53 years. Physicians underestimated pain intensity relative to their patients 39% of the time. Forty-six percent agreed with their patients' pain perception, and 15% of physicians overestimated their patients' pain levels by > or =2 points. In both the bivariate and multivariable models, black race was a significant variable associated with underestimation of pain by physicians (p < 0.05; OR = 1.92; 95% CI: 1.31-2.81). This study finds that physicians are twice as likely to underestimate pain in blacks patients compared to all other ethnicities combined. A qualitative study exploring why physicians rate blacks patients' pain low is warranted.

Cracked and broken teeth--definitions, differential diagnosis and treatment

Cracked and broken teeth present a diagnostic dilemma to the dentist and the sooner a correct diagnosis is made the greater are the chances to save the tooth. As the location, direction and size of the crack or fracture dictates the choice of treatment, it is important to first define the types of cracks and fractures in the coronal and radicular tooth structure. Cracks and fractures can be classified as follows: 1. craze lines 2. fractured cusps 3. cracked teeth 4. split teeth 5. vertical root fractures. The vertical root fracture has been described recently in two articles in this publication, and therefore will not be discussed here. Diagnosis of a cracked tooth is not always initially obvious. The patient's response to clinical testing is the primary diagnostic tool along with the dental history provided by the patient. Radiographs are secondary in making a diagnosis. Clinical aids for reproducing the patient's symptoms such as occlusal bite devices, observing occlusal wear facets and the application of cold water to one tooth at a time may isolate the offending tooth. In situations where an irreversible pulpitis is diagnosed, endodontic treatment is indicated. In the case of a questionable diagnosis, or one in which a potential reversible pulpitis is made, a provisional restoration can be placed for an unspecified time as a diagnostic aid. If endodontic therapy were indicated, consultation with the patient as to the compromised prognosis and the alternatives to endodontic treatment is essential.

The Influence of Discordance in Pain Assessment on the Functional Status of Patients with Chronic Nonmalignant Pain

BACKGROUND

Chronic pain is a frequent cause of suffering and disability that seriously affects patients' quality of life and imposes a staggering socioeconomic toll on society. Little is known about the impact of patient-physician disagreement (discordance) regarding the assessment of chronic pain on patients' quality of life in primary care settings. This study evaluates the role of discordance and other potentially modifiable factors that affect the quality of life and functional status of chronic pain patients.

METHODS

We evaluated 436 patient-physician encounters at 12 academic medical centers in the United States. We surveyed chronic nonmalignant pain patients to understand their pain perceptions. We concurrently surveyed their physicians about their perceptions of their patient's pain in primary care settings.

RESULTS

More than 50% of physicians disagreed with their patient's pain. Thirty-nine percent of primary care physicians underestimated their patient's pain. In the multivariate analysis, this discordance was associated with poor physical functioning and worse bodily pain (P < 0.018 and P < 0.001 respectively). Patients with chronic, nonmalignant pain have reductions in physical function and bodily pain domains of the SF-36 compared to age-matched populations. Depression and obesity represented other associations.

CONCLUSION

Patients with chronic nonmalignant pain have poor physical functioning and worse bodily pain. Discordance, obesity, and depression are other modifiable factors. Prospective studies are needed to design interventions. However, a multifaceted approach appears to represent the best opportunity to reduce the pain and suffering of this challenging population.

Thalassomonas loyana sp. nov., a causative agent of the white plague-like disease of corals on the Eilat coral reef

The taxonomic position of the coral pathogen strain CBMAI 722T was determined on the basis of molecular and phenotypic data. We clearly show that the novel isolate CBMAI 722 T is a member of the family Colwelliaceae, with Thalassomonas ganghwensis as the nearest neighbour (95 % 16S rRNA gene sequence similarity). CBMAI 722T can be differentiated from its nearest neighbour on the basis of phenotypic and chemotaxonomic features, including the utilization of cellobiose and L-arginine, the production of alginase and amylase, but not oxidase, and the presence of the fatty acids 12:0 3-OH and 14:0, but not 10:0 or 15:0. The DNA G+C content of CBMAI 722T is 39.3 mol%. We conclude that this strain represents a novel species for which we propose the name Thalassomonas loyana sp. nov., with the type strain CBMAI 722T (=LMG 22536T). This is the first report of the involvement of a member of the family Colwelliaceae in coral white plague-like disease.

Fluctuations of functionally distinct CD8+ T-cell clonotypes demonstrate flexibility of the HIV-specific TCR repertoire

T-cell receptor (TCR) diversity of virus-specific CD8+ T cells likely helps prevent escape mutations in chronic viral infections. To understand the dynamics of the virus-specific T cells in more detail, we followed the evolution of the TCR repertoire specific for a dominant HLA-B*08-restricted epitope in Nef (FLKEKGGL) in a cohort of subjects infected with HIV. Epitope-specific CD8+ T cells used structurally diverse TCR repertoires, with different TCRbeta variable regions and with high amino acid diversity within antigen recognition sites. In a longitudinal study, distinct Vbeta populations within the HIV-specific TCR repertoire expanded simultaneously with changes in plasma viremia, whereas other Vbeta populations remained stable or even decreased. Despite antigenic variation in some subjects, all subjects had the consensus sequence present during the study period. Functional analysis of distinct Vbeta populations revealed differences in HIV-specific IFN-gamma secretion ex vivo as well as differences in tetramer binding, indicating functional heterogeneity among these populations. This contrasts with findings in a subject on antiretroviral therapy with suppression of viremia to less than 50 copies/mL, where we observed long-term persistence of a single clonotype. Our findings illustrate the flexibility of a heterogeneous HIV-1-specific CD8+ TCR repertoire in subjects with partial control of viremia.