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.

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.

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.

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.

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.

Interleukin-6 and glucocorticoids synergistically induce human immunodeficiency virus type-1 expression in chronically infected U1 cells by a long terminal repeat independent post-transcriptional mechanism.

BACKGROUND: Glucocorticoids (GC) such as dexamethasone (Dex) can directly upregulate human immunodeficiency virus type-1 (HIV-1) replication in acutely infected cells and potentiate HIV expression from chronically infected promonocytic U1 cells stimulated with tumor necrosis factor-alpha (TNF-alpha). We have here investigated the potential effect of Dex in U1 cells stimulated with interleukin-6 (IL-6), a cytokine inducing virus expression by acting mostly at a post-transcriptional level on the virus life cycle. MATERIALS AND METHODS: Virus production in culture supernatants was evaluated by reverse transcriptase (RT) activity. GC receptor expression was tested by both binding of [3H]-Dexamethasone 21-mesylate and Northern blotting. Cell-associated HIV protein expression was analyzed by Western blotting, whereas both HIV and monocyte chemoattractant protein-1 (MCP-1) RNA accumulation were evaluated by Northern blotting. HIV transcription was tested by long terminal repeat (LTR) chloramphenicol acetyl transferase (CAT) assay after transient transfection of U1 or U937 cells. Formation of activating protein-1 (AP-1) DNA binding complex in nuclear cell extracts was visualized by electrophoretic mobility shift assay (EMSA), whereas ERK1/2 mitogen-activated protein kinase (MAPK) phosphorylation was studied by Western blotting. RESULTS: IL-6 and Dex synergistically induced HIV expression in U1 cells, and this effect was blocked by RU 486. No substantial HIV RNA accumulation was demonstrated in U1 cells co-stimulated with IL-6 and Dex, whereas IL-6 upregulated the expression of MCP-1 RNA, and this effect was inhibited by Dex. In contrast, Dex potentiated IL-6 induced activation of AP-1 and ERK1/2 MAPK phosphorylation, as revealed by EMSA. HIV-1 LTR driven transcription was observed in U1 cells stimulated with TNF-alpha and this effect was potentiated by Dex. In sharp contrast, no induction of LTR-directed CAT activity was observed in transfected U1 cells (or in their parental uninfected U937 cells) stimulated with IL-6 and Dex either alone or in combination. CONCLUSIONS: High levels of virion production can be induced in latently infected cells by stimulation with IL-6 and Dex in the absence of activation of the HIV LTR or viral transcription in spite of activation of both ERK1/2 MAPK and AP-1. These findings suggest the existence of LTR-independent pathways influenced by cytokine and GC through which HIV can maintain substantial levels of protein expression and virion production.

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.

The binding subunit of pertussis toxin inhibits HIV replication in human macrophages and virus expression in chronically infected promonocytic U1 cells.

We have recently shown that the binding subunit of pertussis toxin (PTX-B) inhibits the entry and replication of macrophage-tropic (R5) HIV-1 strains in activated primary T lymphocytes. Furthermore, PTX-B suppressed the replication of T cell-tropic (X4) viruses at a postentry level in the same cells. In this study we demonstrate that PTX-B profoundly impairs entry and replication of the HIV-1(ADA) (R5), as well as of HIV pseudotyped with either murine leukemia virus or vesicular stomatitis virus envelopes, in primary monocyte-derived macrophages. In addition, PTX-B strongly inhibited X4 HIV-1 replication in U937 promonocytic cells and virus expression in the U937-derived chronically infected U1 cell line stimulated with cytokines such as TNF-alpha and IL-6. Of interest, TNF-alpha-mediated activation of the cellular transcription factor NF-kappaB was unaffected by PTX-B. Therefore, PTX-B may represent a novel and potent inhibitor of HIV-1 replication to be tested for efficacy in infected individuals. In support of this proposition, a genetically modified mutant of PTX (PT-9K/129G), which is safely administered for prevention of Bordetella pertussis infection, showed an in vitro anti-HIV profile superimposable to that of PTX-B.

Dental education: one dean's perspective.

A dean looks at dental education and the practicing profession from the perspective of three years in dental school administration and sixteen in industry. A significant challenge is to balance costs and standards in the face of well-meaning calls for benefits from those who are not charged with meeting costs. One issue of central importance for education is keeping the curriculum properly positioned in a dynamically evolving profession. The knowledge and skills needed to manage the practice pharmacopeia are used as an example of this problem. It is proposed that schools adopt a future orientation. Dental education must be valued within the higher educational community just as dentistry is valued for its contributions to society at large. Any drift toward proprietary interests must be resisted. This can best be accomplished through a partnership between education and organized dentistry where the lobbying power of the ADA is used to gain the resources education needs and where education, including research and patient care aspects of its mission, are enlisted in support of the practicing community.

Professional and community efforts to prevent morbidity and mortality from oral cancer.

BACKGROUND: Oral and pharyngeal cancers cause significant morbidity and mortality, yet there has been little improvement in survival rates in the past 30 years. Because early diagnoses significantly increase survival rates, the authors summarize several approaches to educating and mobilizing the dental profession and the public about this problem. Clinicians are invited to initiate similar programs to catalyze change in their own communities. METHODS: The authors found that many approaches have been used to define the problem and initiate change. These include surveys, focus groups, development of consortia, media programs, flyers, leaflets, prescription pads, legislation and professional endorsements. RESULTS: In Maryland in 1996, only 20 percent of adults reported receiving an oral cancer examination, and most oral cancers were diagnosed at late stages by physicians, not dentists. Results of the public educational campaigns in the regions of New York/New Jersey and Maryland have not been formally evaluated, but there is a developing consensus that oral cancer diagnostic practices in the regions with active educational programs are increasing. CONCLUSIONS: Coalitions or partnerships among individuals and organizations from government, academia, private practice, industry, the general community and the media can affect awareness about oral cancer prevention and early detection on a regional basis. CLINICAL IMPLICATIONS: By increasing awareness of oral cancer among the dental profession and the public, earlier diagnosis of these cancers with consequent improved cure rates is likely. Providing oral cancer diagnostic services as a routine part of an oral examination also may motivate patients to visit the dentist at least once a year.

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 B-oligomer of pertussis toxin inhibits human immunodeficiency virus type 1 replication at multiple stages.

We have recently demonstrated that the binding subunit (B-oligomer) of pertussis toxin (PTX-B) deactivates CCR5 and inhibits entry of R5 human immunodeficiency virus type 1 (HIV-1) strains in activated primary T lymphocytes (M. Alfano et al., J. Exp. Med. 190:597-605, 1999). We now present evidence that PTX-B also affects a post-entry step of HIV-1 replication. While PTX-B inhibited fusion induced by R5 but not that induced by X4 envelopes, it blocked infection of T cells with recombinant HIV-1 particles pseudotyped with R5, X4, and even murine leukemia virus or vesicular stomatitis virus envelopes. It also suppressed HIV-1 RNA synthesis in cultures of infected peripheral blood mononuclear cells when new infections had been inhibited by zidovudine, and it reduced Tat-dependent expression of the luciferase reporter gene controlled by the HIV-1 long terminal repeat (LTR). Surprisingly, PTX-B did not affect expression from the cytomegalovirus promoter, nor did it reduce the basal (Tat-independent) expression from the LTR promoter. These results indicate that PTX-B inhibits HIV-1 infection at both the entry and the post-entry stages of viral replication, with the post-entry activity specifically affecting transcription or stability of Tat-stimulated HIV-1 mRNAs.