Dominant Power and the Concept of Caste: Implications for Dentistry and Oral Health Inequality.

This paper explores the issues of caste and casteism in the U.S. as described by Pulitzer Prize winning journalist Isabel Wilkerson in her 2020 book "Caste: The Origin of Our Discontents". Wilkerson argues that a caste system not only exists in the U.S. but operates as a hidden force affecting social inequality. The paper draws on Wilkerson's work to explore caste as an analytical concept. It begins by defining caste and casteism in contrast with racism, the eight pillars of a caste system, the consequences of casteism, and the psychological drivers of casteism. The paper then applies to concept of caste to understanding power, dentistry, and oral health inequality. The paper concludes by emphasizing that the concept of caste and its relationship to oral health inequality must be understood it if we want to create real social change.

Genetic and pharmacologic modulation of cementogenesis via pyrophosphate regulators.

Pyrophosphate (PPi) serves as a potent and physiologically important regulator of mineralization, with systemic and local concentrations determined by several key regulators, including: tissue-nonspecific alkaline phosphatase (ALPL gene; TNAP protein), the progressive ankylosis protein (ANKH; ANK), and ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1; ENPP1). Results to date have indicated important roles for PPi in cementum formation, and we addressed several gaps in knowledge by employing genetically edited mouse models where PPi metabolism was disrupted and pharmacologically modulating PPi in a PPi-deficient mouse model. We demonstrate that acellular cementum growth is inversely proportional to PPi levels, with reduced cementum in Alpl KO (increased PPi levels) mice and excess cementum in Ank KO mice (decreased PPi levels). Moreover, simultaneous ablation of Alpl and Ank results in reestablishment of functional cementum in dKO mice. Additional reduction of PPi by dual deletion of Ank and Enpp1 does not further increase cementogenesis, and PDL space is maintained in part through bone modeling/remodeling by osteoclasts. Our results provide insights into cementum formation and expand our knowledge of how PPi regulates cementum. We also demonstrate for the first time that pharmacologic manipulation of PPi through an ENPP1-Fc fusion protein can regulate cementum growth, supporting therapeutic interventions targeting PPi metabolism.

Constructing Matched Groups in Dental Observational Health Disparity Studies for Causal Effects.

INTRODUCTION: Electronic health record (EHR) systems provide investigators with rich data from which to examine actual impacts of care delivery in real-world settings. However, confounding is a major concern when comparison groups are not randomized. OBJECTIVES: This article introduced a step-by-step strategy to construct comparable matched groups in a dental study based on the EHR of the Willamette Dental Group. This strategy was employed in preparation for a longitudinal study evaluating the impact of a standardized risk-based caries prevention and management program across patients with public versus private dental insurance in Oregon. METHODS: This study constructed comparable dental patient groups through a process of 1) evaluating the need for and feasibility of matching, 2) considering different matching methods, and 3) evaluating matching quality. The matched groups were then compared for their average ratio in the number of decayed, missing, and filled tooth surfaces (DMFS + dmfs) at baseline. RESULTS: This systematic process resulted in comparably matched groups in baseline covariates but with a clear baseline disparity in caries experience between them. The weighted average ratio in our study showed that, at baseline, publicly insured patients had 1.21-times (95% CI: 1.08 to 1.32) and 1.21-times (95% CI: 1.08 to 1.37) greater number of DMFS + dmfs and number of decayed tooth surfaces (DS + ds) than privately insured patients, respectively. CONCLUSION: Matching is a useful tool to create comparable groups with EHR data to resemble randomized studies, as demonstrated by our study where even with similar demographics, neighborhood and clinic characteristics, publicly insured pediatric patients had greater numbers of DMFS + dmfs and DS + ds than privately insured pediatric patients. KNOWLEDGE TRANSFER STATEMENT: This article provides a systematic, step-by-step strategy for investigators to follow when matching groups in a study-in this case, a study based on electronic health record data. The results from this study will provide patients, clinicians, and policy makers with information to better understand the disparities in oral health between comparable publicly and privately insured pediatric patients who have similar values in individual, clinic, and community covariates. Such understanding will help clinicians and policy makers modify oral health care and relevant policies to improve oral health and reduce disparities between publicly and privately insured patients.

Makings of a brittle bone: Unexpected lessons from a low protein diet study of a mouse OI model.

Glycine substitutions in type I collagen appear to cause osteogenesis imperfecta (OI) by disrupting folding of the triple helix, the structure of which requires Gly in every third position. It is less clear, however, whether the resulting bone malformations and fragility are caused by effects of intracellular accumulation of misfolded collagen on differentiation and function of osteoblasts, effects of secreted misfolded collagen on the function of bone matrix, or both. Here we describe a study originally conceived for testing how reducing intracellular accumulation of misfolded collagen would affect mice with a Gly610 to Cys substitution in the triple helical region of the α2(I) chain. To stimulate degradation of misfolded collagen by autophagy, we utilized a low protein diet. The diet had beneficial effects on osteoblast differentiation and bone matrix mineralization, but also affected bone modeling and suppressed overall animal growth. Our more important observations, however, were not related to the diet. They revealed how altered osteoblast function and deficient bone formation by each cell caused by the G610C mutation combined with increased osteoblastogenesis might make the bone more brittle, all of which are common OI features. In G610C mice, increased bone formation surface compensated for reduced mineral apposition rate, resulting in normal cortical area and thickness at the cost of altering cortical modeling process, retaining woven bone, and reducing the ability of bone to absorb energy through plastic deformation. Reduced collagen and increased mineral density in extracellular matrix of lamellar bone compounded the problem, further reducing bone toughness. The latter observations might have particularly important implications for understanding OI pathophysiology and designing more effective therapeutic interventions.

Identifying communities with low dentist supply in California.

OBJECTIVES: This study estimates the supply and geographic distribution of dentists in California and examines the community characteristics associated with supply of dentists. METHODS: The number of practicing dentists was estimated from American Dental Association data on licensed dentists in California. Each dentist's address was geocoded and matched to a Medical Service Study Area (MSSA). Dentist-to-population ratios were computed, and the association between dentist supply and community characteristics was analyzed in regression models. RESULTS: Approximately 20 percent of California communities may have a shortage of dentists. Two-thirds of dental shortage communities are rural. Communities with a lower supply of dentists have higher percentages of minorities, children, and low-income persons. Minority dentists were more likely to practice in minority communities. CONCLUSIONS: Geographic maldistribution of dentists may contribute to poor access to dental care in many communities, especially in rural, low-income, and minority communities. Minority dentists are more likely to practice in minority communities, but are a small portion of the dental workforce.

Synthetic receptors for CG base pairs.

Hydrogen-bond-mediated complexation of a CG base pair by a hexylureido phthalimide and a hexylureido isoindolin-1-one was studied by (1)H NMR spectroscopy in an organic solvent. Chemical shift data indicate that both receptors effectively bind the CG base pair from the major groove side.

Low dielectric response in enzyme active site.

The kinetics of charge transfer depend crucially on the dielectric reorganization of the medium. In enzymatic reactions that involve charge transfer, atomic dielectric response of the active site and of its surroundings determines the efficiency of the protein as a catalyst. We report direct spectroscopic measurements of the reorganization energy associated with the dielectric response in the active site of alpha-chymotrypsin. A chromophoric inhibitor of the enzyme is used as a spectroscopic probe. We find that water strongly affects the dielectric reorganization in the active site of the enzyme in solution. The reorganization energy of the protein matrix in the vicinity of the active site is similar to that of low-polarity solvents. Surprisingly, water exhibits an anomalously high dielectric response that cannot be described in terms of the dielectric continuum theory. As a result, sequestering the active site from the aqueous environment inside low-dielectric enzyme body dramatically reduces the dielectric reorganization. This reduction is particularly important for controlling the rate of enzymatic reactions.

Free energy of charge transfer and intraprotein electric field: method of calculation depends on the charge state of protein at a given structure.

Free energy of charge transfer presents a basic characteristic of reactions such as protonation, oxido-reduction and similar. Evaluation of this quantity requires calculation of charging energy. Proteins are structured dielectrics, and a consistent incorporation of their structure into calculation of intraprotein electric field results in expression for charging energy of an active group in protein, which is essentially different from that for a simple dielectric. An algorithm for semi-continuum calculation of relevant free energies is described. First of the two components of charging energy in protein, energy of the medium response to charge redistribution in reactants, should be always calculated as the charging energy by the charge redistribution using the static dielectric constant of protein. The second term is interaction energy of the charge redistribution with the 'frozen' electric field of the system before reaction. Charges of protein groups, at which the protein structure has been determined, are often different from those before reaction of charge transfer, so is the corresponding intraprotein field. The field is expressed through either both the optical and static dielectric constants of protein or only optical one depending on whether the charges of protein groups before reaction and upon structural analysis are the same or not. Proper allowance for difference in charges of reacting groups before reaction and upon structural analysis of protein is thermodynamically necessary and quantitatively important. The expression for activation free energy for charge transfer in proteins is derived in the form presenting explicitly an invariant contribution of protein structure.

Electrostatics of proteins: description in terms of two dielectric constants simultaneously.

In the semi-continuum treatment of the energetics of charge formation (or transfer) inside a protein, two components of the energy are inevitably present: the energy of interaction of the ion with the pre-existing intraprotein electric field, and the energy due to polarization of the medium by the newly formed charge. The pre-existing field is set up by charges (partial or full) of the protein atoms fixed in a definite structure. The calculation of this field involves only the electronic polarization (the optical dielectric constant epsilon(o)) of the protein because the polarization due to shifts of heavy atoms has already been accounted for by their equilibrium coordinates. At the same time, the aqueous surroundings should be described by the static constant epsilon(sw), as the positions of water molecules are not fixed. The formation of a new charge, absent in the equilibrium X-ray structure, results in shifts of electrons and polar atoms, i.e., it involves all kinds of medium polarization described by the static dielectric constant of protein epsilon(s). Thus, in calculations of the total energy, two different dielectric constants of the protein are operative simultaneously. This differs from a widely used algorithm employing one effective dielectric constant for both components of the ion's energy.

A dangerous direction: legal intervention in sexual abuse survivor therapy.

In this Article, Professors Bowman and Mertz question recent popular and academic commentary that disputes the validity of all delayed-recall memories of childhood sexual abuse. They examine one court's decision to allow a father, accused by his daughter of childhood sexual abuse, to recover malpractice damages from his daughter's therapist in connection with therapy during which the daughter recovered memories of the abuse. The authors argue that such third-party liability is unsound in terms of established principles of tort doctrine and in terms of public policy. After a review of the scientific evidence, the authors further conclude that, although some memories may be inaccurate, delayed-recall memory can also accurately reflect that past abuse occurred. Permitting third-party liability against therapists when accurate memories of abuse surface in therapy gives abusers a weapon to use against their victims. Because such suits exclude the party in privity (the client), they effectively erase the victim's voice. Professors Bowman and Mertz argue that such a novel extension of third-party liability is at best a misuse of the courts' resources and ultimately harms abuse survivors, therapists, and the community far more than it helps any wrongfully accused parents.

In vitro digestibility and amino acid composition of pearl millet (Pennisetum typhoides) and other cereals.

The purpose of this study was to compare in vitro digestibility, protein distribution patterns, and amino acid composition of pearl millet with other major cereals. Digestibility values for the pearl millet varieties were higher than that of sorghum and comparable to that of maize. In contrast to sorghum, digestibility of pearl millet and maize did not decrease significantly upon cooking. Protein distribution patterns of uncooked pearl millet and shifts in the different fractions as a result of cooking also resembled that of maize and not sorghum. The amino acid profile of pearl millet is more favorable than that of normal sorghum and normal maize and is comparable to the small grains, wheat, barley, and rice. On the basis of these findings, it appears that pearl millet is a nutritious and well-digested source of calories and proteins for humans.

Improving the in vitro protein digestibility of sorghum with reducing agents.

We have shown in previous reports that cooked sorghum protein is less digestible than other cooked cereal proteins. The pepsin-indigestible proteins in sorghum were found to be mainly prolamin proteins. Cooking sorghum in the presence of 2-mercaptoethanol increased protein digestibility (in vitro with pepsin or trypsin/chymotrypsin) to a level comparable with other cereals. At a concentration of 100 mM, other reducing agents (dithiothreitol, sodium bisulfite, and L-cysteine) were equally effective in improving sorghum digestibility. When maize was cooked in the presence of 2-mercaptoethanol, protein digestibility increased 5% compared to 25% for sorghum. Cooking barley, rice, and wheat with 2-mercaptoethanol had no significant effect on protein digestibility. The addition of reducing agents appears to prevent the formation of protein polymers linked by disulfide bonds.

Digestibility and utilization of protein and energy from Nasha, a traditional Sudanese fermented sorghum weaning food.

Whole grain sorghum flour was fermented into Nasha, a traditional Sudanese food, and freeze-dried or drum-dried. It was cooked and fed to convalescent malnourished infants and small children as 61% of total diet calories and all of 6.4% protein calories, with (Lys+) and without lysine supplementation to 3% of protein. Apparent absorptions of nitrogen were 73 +/- 5 and 74 +/- 6% of intake, significantly (P less than 0.01) less than those from preceding (Cas-1, 86 +/- 3%) and following (Cas-2, 85 +/- 3%) isonitrogenous casein diets. Apparent retentions of nitrogen from Nasha (26 +/- 10%) were significantly lower than those from Lys + (34 +/- 9%, P less than 0.05), Cas-1 (35 +/- 11%, P less than 0.01) or Cas-2 (49 +/- 9%, P less than 0.01). Retentions from Cas-2 were higher than those from Cas-1 or Lys + (P less than 0.01). Fecal wet and dry weights were higher (P less than 0.02) during both Nasha diets and Cas-2 than during Cas-1. Fecal energy and carbohydrate were significantly (P less than 0.01) higher from either Nasha diet than from either casein diet; fecal fat was not different. Two children received drum-dried Nasha without further cooking; digestibilities were not different from those of the cooked product but biological value was much lower. When properly cooked and consumed along with small amounts of a good source of lysine, Nasha is a satisfactory weaning food.

The influence of positive affect on the unusualness of word associations.

A pilot study and two experiments investigated the influence of positive affect, induced in three differing ways, on the uniqueness of word associations. Persons in the positive-affect conditions gave more unusual first-associates to neutral words, according to the Palermo & Jenkins (1964) norms, than did subjects in the control conditions. In Study 3, where word type (positive, neutral, negative) was a second factor along with affect, in a between-subjects design, associates to positive words were also more unusual and diverse than were those to other words. These results were related to those of studies suggesting that positive affect may facilitate creative problem solving and to other work suggesting an impact of positive feelings on cognitive organization.

Pepsin digestibility of proteins in sorghum and other major cereals.

We have shown previously that sorghum is highly digestible in the rat. However, other workers have shown that sorghum is much less digestible than wheat, maize, and rice in young children. Because the rat does not show these digestibility differences, we developed an empirical pepsin digestion method, first reported in 1981, which simulates the digestion values found in children. In this report the method has been improved and used to analyze wheat, maize, rice, millet, and sorghum and certain processed samples of millet and sorghum. The pepsin digestion values parallel those found in children for wheat, maize, rice, and sorghum. In addition, a processed sorghum product that gave a high digestion value in children also gave a high value with the in vitro pepsin method.

Digestibility of sorghum proteins.

Published information indicates that rice, maize, and wheat proteins are much more digestible in children than sorghum proteins are (66-81% compared with 46%). However, this digestibility difference cannot be demonstrated with the weanling rat, which gave digestibility values of 80% for cooked and 85% for uncooked sorghum gruels. Therefore, a search was made for a laboratory system sensitive to the digestibility differences between sorghum and other cereals. We found that porcine pepsin in vitro shows these digestibility differences. Using pepsin, we have found that uncooked sorghum proteins have a high digestibility (78-100%), which drops to a range of 45-55% after cooking. Two fermented sheet-baked sorghum products (kisra and abrey) from Sudan gave pepsin digestibility values of 65-86%. In contrast, unfermented cooked gruels made in our laboratory from the same flours used for the kisra and abrey gave pepsin values of only 44-56%. Therefore, fermentation improves pepsin digestibility of sorghum. The digestibility values of other sorghum-based foods prepared in the semiarid tropics need surveying. Those with high pepsin digestibility values hopefully should be more digestible (in children) than are the cooked sorghum gruels studied to date by human nutritionists.

Plasmin-mediated proteolysis of casein in bovine milk.

Plasminogen was found to be present in bovine milk by crossreactivity between rabbit antiserum to plasminogen and casein prepared from milk by acid precipitation. This result was further supported by recovery of intact 125I-labeled plasminogen from rabbit milk after its intravenous injection. Freshly isolated whole bovine casein was observed to undergo slow autoproteolysis at 37 degrees C. Polyacrylamide gel electrophoresis revealed gradual disappearance of major caseins accompanied by appearance and increase in intensity of numerous electrophoretic bands. This autoproteolysis was inhibited by low concentrations of epsilon-aminocaproic acid (0.1 mM) and diisopropyl fluorophosphate (1 mM); catalytic amounts of urokinase accelerated the process. Autoproteolysis of isolated bovine beta-casein was shown by both urea and sodium dodecyl sulfate gel electrophoresis to result in formation of gamma 1- and gamma 2-caseins. Similar electrophoretic bands were formed when beta-casein was degraded by plasmin prepared from bovine blood serum. These results support the hypothesis that bovine plasmin occurs in milk and is identical to alkaline milk protease.