Biophysical and structural characterization of the putative nickel chaperone CooT from Carboxydothermus hydrogenoformans.

Carboxydothermus hydrogenoformans is a model microorganism for the study of [NiFe]-CODH, a key enzyme of carbon cycle in anaerobic microorganisms. The enzyme possesses a unique active site (C-cluster), constituted of a distorted [NiFe3S4] cubane linked to a mononuclear Fe(II) center. Both the biogenesis of the C-cluster and the activation of CODH by nickel insertion remain unclear. Among the three accessory proteins thought to play a role in this latter step (CooC, CooJ, and CooT), CooT is identified as a nickel chaperone involved in CODH maturation in Rhodospirillum rubrum. Here, we structurally and biophysically characterized a putative CooT protein present in C. hydrogenoformans (pChCooT). Despite the low sequence homologies between CooT from R. rubrum (RrCooT) and pChCooT (19% sequence identity), the two proteins share several similarities, such as their overall structure and a solvent-exposed Ni(II)-binding site at the dimer interface. Moreover, the X-ray structure of pChCooT reveals the proximity between the histidine 55, a potential nickel-coordinating residue, and the cysteine 2, a highly conserved key residue in Ni(II)-binding.

Harold C. Slavkin: A Transformative Leader of Our Times.

Harold (Hal) C. Slavkin, DDS, the 22nd president of the American Association for Dental, Oral, and Craniofacial Research (1993 to 1994), died on December 22, 2023. During a career that spanned almost 6 decades, Hal distinguished himself as an international authority on craniofacial biology and an advocate for oral health equity. He served as dean of the University of Southern California's dental school, founded the school's Center for Craniofacial Molecular Biology, created the nation's first PhD program in craniofacial biology, and served as the sixth director of the National Institute of Dental and Craniofacial Research. Hal's studies of the molecular and cellular underpinnings of craniofacial malformations prepared him to champion translational research later in his career, when his work with patient advocates revealed the importance of applying new discoveries to clinical practice. A visionary thinker, skilled administrator, progressive educator, compelling communicator, researcher, scholar, and mentor, Hal was known as a Renaissance leader. He rejoiced in fostering collaborative synergies among people and organizations. Throughout his life, family was his central grounding force. He and his wife, Lois, advanced a wide range of social and community initiatives and took great pride in their children, grandchildren, and great-grandchildren. We remember Hal for his indelible spirit, unflappable enthusiasm for science, fierce advocacy for social justice, and infectious zest for life. Here, we outline his multidimensional accomplishments through the lenses of academia, government, and nonprofit organizations. Although it is with heavy hearts that we bid goodbye to this remarkable man, our spirits are lightened by the many gifts he left behind.

Native extracellular matrix probes to target patient- and tissue-specific cell-microenvironment interactions by force spectroscopy.

Atomic Force Microscopy (AFM) is successfully used for the quantitative investigation of the cellular mechanosensing of the microenvironment. To this purpose, several force spectroscopy approaches aim at measuring the adhesive forces between two living cells and also between a cell and an appropriate reproduction of the extracellular matrix (ECM), typically exploiting tips suitably functionalised with single components (e.g. collagen, fibronectin) of the ECM. However, these probes only poorly reproduce the complexity of the native cellular microenvironment and consequently of the biological interactions. We developed a novel approach to produce AFM probes that faithfully retain the structural and biochemical complexity of the ECM; this was achieved by attaching to an AFM cantilever a micrometric slice of native decellularised ECM, which was cut by laser microdissection. We demonstrate that these probes preserve the morphological, mechanical, and chemical heterogeneity of the ECM. Native ECM probes can be used in force spectroscopy experiments aimed at targeting cell-microenvironment interactions. Here, we demonstrate the feasibility of dissecting mechanotransductive cell-ECM interactions in the 10 pN range. As proof-of-principle, we tested a rat bladder ECM probe against the AY-27 rat bladder cancer cell line. On the one hand, we obtained reproducible results using different probes derived from the same ECM regions; on the other hand, we detected differences in the adhesion patterns of distinct bladder ECM regions (submucosa, detrusor, and adventitia), in line with the disparities in composition and biophysical properties of these ECM regions. Our results demonstrate that native ECM probes, produced from patient-specific regions of organs and tissues, can be used to investigate cell-microenvironment interactions and early mechanotransductive processes by force spectroscopy. This opens new possibilities in the field of personalised medicine.

Micro-mechanical fingerprints of the rat bladder change in actinic cystitis and tumor presence.

Tissue mechanics determines tissue homeostasis, disease development and progression. Bladder strongly relies on its mechanical properties to perform its physiological function, but these are poorly unveiled under normal and pathological conditions. Here we characterize the mechanical fingerprints at the micro-scale level of the three tissue layers which compose the healthy bladder wall, and identify modifications associated with the onset and progression of pathological conditions (i.e., actinic cystitis and bladder cancer). We use two indentation-based instruments (an Atomic Force Microscope and a nanoindenter) and compare the micromechanical maps with a comprehensive histological analysis. We find that the healthy bladder wall is a mechanically inhomogeneous tissue, with a gradient of increasing stiffness from the urothelium to the lamina propria, which gradually decreases when reaching the muscle outer layer. Stiffening in fibrotic tissues correlate with increased deposition of dense extracellular matrix in the lamina propria. An increase in tissue compliance is observed before the onset and invasion of the tumor. By providing high resolution micromechanical investigation of each tissue layer of the bladder, we depict the intrinsic mechanical heterogeneity of the layers of a healthy bladder as compared with the mechanical properties alterations associated with either actinic cystitis or bladder tumor.

Dental Services and Health Outcomes in the New York State Medicaid Program.

Previous reports suggest that periodontal treatment is associated with improved health care outcomes and reduced costs. Using data from the New York State Medicaid program, rates of emergency department (ED) use and inpatient admissions (IPs), as well as costs for ED, IPs, pharmacy, and total health care, were studied to determine the association of preventive dental care to health care outcomes. Utilization of dental services in the first 2 y (July 2012-June 2014) was compared to health care outcomes in the final year (July 2014-June 2015). Costs and utilization for members who did not receive dental services (No Dental) were compared to those who received any dental care (Any Dental), any preventive dental care (PDC), PDC without an extraction and/or endodontic treatment (PDC without Ext/Endo), PDC with an Ext/Endo (PDC with Ext/Endo), or Ext/Endo without PDC (Ext/Endo without PDC). Propensity scores were used to adjust for potential confounders. After adjustment, ED rate ratios were significantly lower for PDC and PDC without Ext/Endo but higher for the Any Dental and Ext/Endo without PDC. IP ratios were lower for all treatment groups except Ext/Endo without PDC. ED costs differed little compared to the No Dental group except for Ext/Endo without PDC. For IPs, costs per member were significantly lower for all groups (-$262.91 [95% confidence interval (CI), -325.40 to -200.42] to -$379.82 [95% CI, -451.27 to -308.37]) except for Ext/Endo without PDC. For total health care costs, Ext/Endo without PDC had a significantly greater total health care cost ($530.50 [95% CI, 156.99-904.01]). Each additional PDC visit was associated with a 3% reduction in the relative risk for ED and 9% reduction for IPs. Costs also decreased for total health care (-$235.64 [95% CI, -299.95 to -171.33]) and IP (-$181.39 [95% CI, -208.73 to -154.05]). In conclusion, an association between PDC and improved health care outcomes was observed, with the opposite association for Ext/Endo without PDC.

The B-oligomer of pertussis toxin deactivates CC chemokine receptor 5 and blocks entry of M-tropic HIV-1 strains.

Infection of target cells by HIV-1 requires initial binding interactions between the viral envelope glycoprotein gp120, the cell surface protein CD4, and one of the members of the seven-transmembrane G protein-coupled chemokine receptor family. Most primary isolates (R5 strains) use chemokine receptor CCR5, but some primary syncytium-inducing, as well as T cell line-adapted, strains (X4 strains) use the CXCR4 receptor. Signaling from both CCR5 and CXCR4 is mediated by pertussis toxin (PTX)-sensitive G(i) proteins and is not required for HIV-1 entry. Here, we show that the PTX holotoxin as well as its binding subunit, B-oligomer, which lacks G(i)-inhibitory activity, blocked entry of R5 but not X4 strains into primary T lymphocytes. Interestingly, B-oligomer inhibited virus production by peripheral blood mononuclear cell cultures infected with either R5 or X4 strains, indicating that it can affect HIV-1 replication at both entry and post-entry levels. T cells treated with B-oligomer did not initiate signal transduction in response to macrophage inflammatory protein (MIP)-1beta or RANTES (regulated upon activation, normal T cell expressed and secreted); however, cell surface expression of CCR5 and binding of MIP-1beta or HIV-1 to such cells were not impaired. The inhibitory effect of B-oligomer on signaling from CCR5 and on entry of R5 HIV-1 strains was reversed by protein kinase C (PKC) inhibitors, indicating that B-oligomer activity is mediated by signaling events that involve PKC. B-oligomer also blocked cocapping of CCR5 and CD4 induced by R5 HIV-1 in primary T cells, but did not affect cocapping of CXCR4 and CD4 after inoculation of the cultures with X4 HIV-1. These results suggest that the B-oligomer of PTX cross-deactivates CCR5 to impair its function as a coreceptor for HIV-1.

Primary, secondary and compensated hypogonadism: a novel risk stratification for infertile men.

Recently, the cohort of men from the European Male Ageing Study has been stratified into different categories distinguishing primary, secondary and compensated hypogonadism. A similar classification has not yet been applied to the infertile population. We performed a cross-sectional study enrolling 786 consecutive Caucasian-European infertile men segregated into eugonadal [normal serum total testosterone (≥3.03 ng/mL) and normal luteinizing hormone (≤9.4 mU/mL)], secondary (low total testosterone, low/normal luteinizing hormone), primary (low total testosterone, elevated luteinizing hormone) and compensated hypogonadism (normal total testosterone; elevated luteinizing hormone). In this cross-sectional study, logistic regression models tested the association between semen parameters, clinical characteristics and the defined gonadal status. Eugonadism, secondary, primary and compensated hypogonadism were found in 80, 15, 2, and 3% of men respectively. Secondary hypogonadal men were at highest risk for obesity [OR (95% CI): 3.48 (1.98-6.01)]. Primary hypogonadal men were those at highest risk for azoospermia [24.54 (6.39-161.39)] and testicular volume <15 mL [12.80 (3.40-83.26)]. Compensated had a similar profile to primary hypogonadal men, while their risk of azoospermia [5.31 (2.25-13.10)] and small testicular volume [8.04 (3.17-24.66)] was lower. The risk of small testicular volume [1.52 (1.01-2.33)] and azoospermia [1.76 (1.09-2.82)] was increased, although in a milder fashion, in secondary hypogonadal men as well. Overall, primary and compensated hypogonadism depicted the worst clinical picture in terms of impaired fertility. Although not specifically designed for infertile men, European Male Ageing Study categories might serve as a clinical stratification tool even in this setting.

Deletion of the thymidine kinase gene induces complete attenuation of the Georgia isolate of African swine fever virus.

African swine fever virus (ASFV) is the etiological agent of a contagious and often lethal viral disease of domestic pigs. There are no vaccines to control Africa swine fever (ASF). Experimental vaccines have been developed using genetically modified live attenuated ASFVs obtained by specifically deleting virus genes involved in virulence, including the thymidine kinase (TK) gene. TK has been shown to be involved in the virulence of several viruses, including ASFV. Here we report the construction of a recombinant virus (ASFV-G/V-ΔTK) obtained by deleting the TK gene in a virulent strain of ASFV Georgia adapted to replicate in Vero cells (ASFV-G/VP30). ASFV-G/P-ΔTK demonstrated decreased replication both in primary swine macrophage cell cultures and in Vero cells compared with ASFV-G/VP30. In vivo, intramuscular administration of up to 10(6) TCID50 of ASFV-G/V-ΔTK does not result in ASF disease. However, these animals are not protected when challenged with the virulent parental Georgia strain.

Divergent regulation of HIV-1 replication in PBMC of infected individuals by CC chemokines: suppression by RANTES, MIP-1alpha, and MCP-3, and enhancement by MCP-1.

We investigated the role of different CC chemokines, including regulated upon activation normal T cell expressed and secreted (RANTES), macrophage inflammatory protein-lalpha (MIP-1alpha), monocyte chemotactic protein-1 (MCP-1), and MCP-3 on virus replication in cultures established from CD8+ T cell-depleted peripheral blood mononuclear cells (PBMC) of HIV-infected individuals that were either cocultivated with allogeneic T cell blasts (ATCB) of uninfected individuals or directly stimulated by mitogen plus interleukin-2. RANTES was the only chemokine that showed a clear-cut suppressive effect on HIV replication in both culture systems, although inhibitory effects were frequently also observed with MIP-1alpha, MCP-3, and, occasionally, with MCP-1. In contrast, MCP-1 frequently enhanced HIV production in most patients' cultures or cocultures that were characterized by secreting relatively low levels (<20 ng/mL) of MCP-1. When CD8-depleted PBMC of HIV+ individuals were cocultivated with ATCB of uninfected healthy donors, a positive correlation was observed between MCP-1 concentrations and the enhancement of HIV-1 replication occurring after depletion of CD8+ cells from donors' cells. Depletion of CD14+ cells (monocytes) from ATCB resulted in the down-regulation of virus replication during co-cultivation with CD8-depleted PBMC of infected individuals. Of interest, MCP-1 up-regulated HIV production in these CD14-depleted ATCB cocultures. Altogether these observations suggest that MCP-1 may represent an important factor enhancing HIV spreading, particularly in anatomical sites, such as the brain, where infection of macrophages and microglial cells plays a dominant role.

The cytokine network in HIV infection.

Cytokines are major controller of HIV replication and represent, at the same time, a target for viral-induced immune dysregulation. This mutual relationship has profound implications for both active HIV replication and immune-mediated governance of latency; in addition, cytokines have therapeutic value in the perspective of immune reconstitution. In the current article we will review the most relevant aspects emerged in almost 20 years of research in this area with particular reference to the distinct, but interconnected contribution of the most simple (cell lines) to the most complex (animal) models of HIV infection.

Urinary output of hydroxylysine glycosides and pyridinium cross-links in detecting rat bone collagen turnover rate.

Glucosylgalactosylhydroxylysine (GGHYL), galactosylhydroxylysine (GHYL), pyridinoline (PYD) and deoxypyridinoline (DPD) were measured in the urine (6 h serial specimens over 96 and 24 h urine specimens for 4 days) collected from four adult Sprague Dawley rats and in the femoral and tibia] bone as well as in the dorsal skin of the same rats. No significant daily variations were found in the urine excretion of GGHYL, GHYL, PYD and DPD but significant diurnal variations. The GGHYL/GHYL ratio in rat urine (0.46 +/- 0.1) reflected neither the bone collagen ratio (1.9 to 2.4) nor the skin collagen ratio (1.22 +/- 1.07), a finding that may reflect GGHYL conversion into GHYL. The content of both pyridinolines was very low in the skin and high in the bone collagen and the urinary PYD/DPD ratio (1.46 +/- 0.15) reflected essentially the bone collagen ratio (0.8-3.0). These results suggest the usefulness of measuring GGHYL, GHYL, PYD and DPD in 24 h urine specimen and, based on the inter-animal variations, the necessity to consider each animal as its own control when bone turnover needs to be monitored.

Deficiency of total collagen content and of deoxypyridinoline in intracranial aneurysm walls.

The tissue contents of total collagen and of 3-hydroxypyridinium cross-links, pyridinoline (PYD) and deoxypyridinoline (DPD), were measured in 15 samples of human aneurysms of Willis' Circle obtained at surgery and in 25 autopsy control samples of intracranial arteries of Willis' Circle obtained from 6 subjects who died of other causes than cerebral hemorrhage. PYD and DPD were detected fluorimetrically after HPLC separation. Total collagen content was significantly lower (P < 0.001) in aneurysm samples (mean +/- S.E.M. 2.50 +/- 0.33 nmol of alpha 1(I) collagen chain per mg of delipidated and dried material) than in controls (mean +/- S.E.M. 3.86 +/- 0.14). DPD, but not PYD, content appears to be lower in aneurysm walls. In the aneurysms, the tissue contents of PYD ranged from 212 to 587 pmol/nmol of alpha 1(I) collagen chain (mean +/- S.E.M. 430 +/- 31) while in control samples the values observed ranged from 292 to 642 (mean +/- S.E.M. 471 +/- 21). The tissue content of DPD was measurable only in 6 aneurysm samples (60%), ranging from 12 to 60 pmol/nmol of alpha 1(I) collagen chain (mean +/- S.E.M. 33 +/- 9), while in control samples, DPD content ranged from 30 to 123 (mean +/- S.E.M. 75 +/- 5).

Cytokine and chemokine based control of HIV infection and replication.

HIV infects and propagates into CD4+ T lymphocytes and macrophages, although many other cell types play an important role in virus spreading and pathogenesis. In addition to regulatory viral proteins, the cytokine network has early been implicated as a major controller of the plastic capacity of HIV to spread productively or rather remain silently integrated in the chromosomes of infected cells. The recent discovery of CCR5 and CXCR4 as essential entry co-receptors together with CD4 has highlighted a novel and potentially important step in the pharmacological hunt for more effective antiviral agents. In addition to regulate HIV expression and replication, several cytokines have demonstrated the capacity of up- or down-modulating chemokine receptors including CCR5 and CXCR4 with the consequence of influencing the susceptibility of T cells and macrophages to HIV infection. Pharmacological agents such as pertussis toxin B-oligomer have demonstrated HIV suppressive effects via non competitive binding of CCR5, whereas interferons or interleukin-16 (IL-16) can prevent post-entry steps in HIV expression. At the clinical level, several cytokines or their receptors are useful markers for monitoring disease progression and its consequence on the immune system. Cytokine-based therapy represents a realistic complementary approach to traditional antiretroviral therapy potentially capable of restoring important adaptive or innate immune functions ultimately curtailing HIV spreading and its consequences on the immune system, as exemplified by the experimental clinical use of IL-2.

Lingual ascorbic acid test: poor correlation with blood and tissue levels of ascorbic acid in guinea pigs.

The lingual ascorbic acid test, based on the reduction and decolorization of the blue dye, 2,6-dichloroindophenol sodium, was evaluated in a group of guinea pigs conditioned to have a wide range of ascorbic acid levels in the tissues. The test did not correlate well with ascorbic acid levels in either blood or tissue.

Localization of rate-limiting barrier to penetration of endotoxin through nonkeratinized oral mucosa in vitro.

The penetration of tritiated bacterial endotoxin through nonkeratinized oral mucosal epithelium was studied using an in vitro model system and radioautographic tracer techniques. The basement membrane region of the epithelium was the rate-limiting barrier to penetration, and this barrier effect was independent of the direction and duration of penetration as well as any clearance effects of the vasculature.

When depression breeds contempt: reassurance seeking, self-esteem, and rejection of depressed college students by their roommates.

To test Coyne's (1976b) theory of depression, students' levels of depressive symptoms, reassurance seeking, and self-esteem were assessed at Time 1, and their same-gender roommates' appraisals of them were assessed 5 weeks later. Mildly depressed students engaged in the type of reassurance seeking described by Coyne. Among men, but not women, mildly depressed students were rejected if they strongly sought reassurance and had low self-esteem but not if they did not seek reassurance or had high self-esteem. Although induction of depressed symptoms in roommates did occur, this contagion effect did not account for the depression-rejection relationship. The prediction that unsupportive, intolerant, or unempathic others would be particularly likely to respond with rejection to reassurance-seeking depressed students with low self-esteem received partial support. Implications for future work on the interpersonal aspects of depression are discussed.

Compensation equity between men and women in academic medicine: methods and implications.

BACKGROUND: Compensation inequity by gender is a problem across occupations in the United States. Most compensation-monitoring efforts in academic medicine have been informal. The authors developed an analytic method for formal, ongoing evaluation of compensation equity in academic medicine. METHOD: A historical cohort study was conducted at Michigan State University College of Medicine using data from 1990, 1991, and 1992 to (1) evaluate methods for monitoring compensation equity, (2) test the feasibility of compensation-equity monitoring as part of administrative information systems, and (3) determine whether compensation inequity existed in a case study of faculty salaries. Internal market adjustments for specialty, clinical or basic science "type," and calendar- or academic-year appointments were made before establishing a male cohort for each female faculty member. RESULTS: The method developed appears feasible for routine administrative monitoring of compensation equity. When the compensations of women of each type and rank were compared with the compensations of their male cohorts, inequities appeared to exist for basic scientists, but not clinicians, based on a criterion of the groups' compensations being 4% or more below those of their cohorts for two successive years. CONCLUSION: The authors suggest that formal monitoring of compensation equity is an important and feasible administrative undertaking to correct historical inequities. This is an area in which leadership by U.S. medical colleges is needed.

Granulocyte/monocyte apheresis induces sustained increases in CD4 T cells in HIV-1 infected patients with poor CD4 T cell restoration after suppression of viral replication by HAART.

Current antiretroviral regimens (HAART) are generally effective in reducing viral replication to undetectable levels and inducing a raise in CD4 T cells. However, in approximately 5 to 15% of patients suppression of viral replication is not followed by an increase in CD4 T cells. Such patients may be at increased risk for opportunistic infections. Here we report the results from a phase II open label randomised trial on 30 patients classified as poor responders to HAART who were either subjected to eight consecutive cycles of selective monocyte apheresis or maintained under HAART alone. The results show that monocyte apheresis results in increased CD4 T cell counts which are maintained for at least 31 weeks after last apheresis. This effect was observed only on patients with complete suppression of viral replication. Other effects of monocyte apheresis included a strong reduction of TNF-alpha production in patients with high baseline levels of this cytokine and activation of resting T cells during the apheresis cycles. In two patients with high cellular HIV DNA load apheresis was followed by a 98% reduction, suggesting purging of infected cells. There was no evidence of increased viral replication during or after the apheresis cycles. The data show that monocyte apheresis is safe, well tolerated and may be indicated in patients who respond poorly to HAART.

Preserved scleral allografts in periodontal defects in man. II. Histological evaluation.

1. The scleral grafts appeared to be well accepted as there were no signs of antigenicity or untoward reactions. 2. The gingival connective tissue, periodontal ligament and the periosteum were observed intertwined with sclera at the interface. 3. Sclera was invaded by host fibroblasts, capillaries, and appeared in some areas to be raplaced by a dense connective tissue. 4. Areas of cementogenesis could be observed in all specimens. 5. There were no signs of osteogenesis within the scleral grafts. 6. The alveolar crest appeared relatively nonreactive to sclera. 7. There were no signs of external root resorption or ankylosis. 8. Sclera may be able to be used to fill in osseous craters, other periodontal defects and as a scaffolding in conjunction with osseous grafts. This requires further investigation. 9. Sclera may possibly be used in areas where there was loss of gingival contour or need for ridge augmentation.

The effect of intrasulcular brushing on sulcular epithelial permeability.

The purpose of the present study was to determine the effect of intrasulcular toothbrushing on permeability of the sulcular epithelium. Twenty-four dental students were divided into two groups of 12 each. On day 0, subjects in Group I began having the buccal aspects of the maxillary right first and second molars brushed for 30 seconds daily for 49 days by an examiner using an intrasulcular technique while subjects in Group II had the same teeth brushed with an extrasulcular technique. On day 49, clinical evaluation of inflammation was performed and biopsies were taken to evaluate gingival inflammation, sulcular epithelial keratinization and permeability of the sulcular epithelium in vitro using a microperfusion technique. Results indicate that subjects in both groups had attained equally high levels of gingival health. The intrasulcular group demonstrated a significantly higher degree of sulcular epithelial keratinization. However, no relationship was found between the degree of sulcular epithelial keratinization and sulcular epithelial permeability. Thus, the benefits derived from intrasulcular brushing and increasing sulcular epithelial keratinization are questionable.